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NB G6 Science study materials
NB G6 Science study resources

NB G6 Science practice questions

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Question 1Scientific Inquiry and Process Skills

A student wants to know whether warm water dissolves sugar faster than cold water. Which statement is the best testable hypothesis?

  1. Sugar dissolves faster in warm water than in cold water. Correct answer.
  2. Warm water is more pleasant to stir than cold water.
  3. Sugar is the best thing to put in water.
  4. Sugar tastes sweeter in warm water than in cold water.

Explanation

A testable hypothesis predicts a specific relationship between two measurable variables that can be checked by experiment. Comparing dissolving speed in warm versus cold water names both the cause (temperature) and the measurable effect (time to dissolve). Statements about taste, pleasantness, or preference cannot be measured with instruments in a fair test.

Question 2Scientific Inquiry and Process Skills

In an experiment testing how light affects plant growth, what is the independent variable?

  1. The height of the plants
  2. The number of leaves on each plant
  3. The amount of light each plant receives Correct answer.
  4. The type of soil used for all plants

Explanation

The independent variable is the factor the experimenter deliberately changes between groups. Here the amount of light is set at different levels to see what happens. Plant height, leaf number, and soil type are either measured outcomes or kept constant.

Question 3Scientific Inquiry and Process Skills

A student measures the mass of the same stone three times and gets 12.1 g, 12.0 g, and 12.1 g. The true mass is 15.0 g. Which statement best describes these results?

  1. They are neither precise nor accurate.
  2. They are accurate but not precise.
  3. They are both accurate and precise.
  4. They are precise but not accurate. Correct answer.

Explanation

Precision means repeated measurements agree closely with one another, while accuracy means they agree with the true value. The three readings cluster tightly together, so they are precise, but all are far from 15.0 g, so they are not accurate. A systematic error such as a misread balance could cause this pattern.

Question 4Scientific Inquiry and Process Skills

Which action is the best example of making a qualitative observation?

  1. Measuring that the block is 4.5 cm long
  2. Recording that the liquid boils at 98 degrees Celsius
  3. Timing that the cart takes 3.2 seconds to roll downhill
  4. Noting that the powder feels gritty between the fingers Correct answer.

Explanation

Qualitative observations describe qualities sensed without measurement, such as texture, color, or smell. Feeling that a powder is gritty is a description rather than a number. The other choices all produce numerical data and are therefore quantitative.

Question 5Scientific Inquiry and Process Skills

A class wants to find out whether fertilizer affects tomato plant height. Which setup is the fairest test?

  1. Two plants of different species, one with fertilizer and one without
  2. Five plants with fertilizer in sunlight and five without fertilizer in shade
  3. One plant given fertilizer and measured every day
  4. Ten plants of the same species, five with fertilizer and five without, all else equal Correct answer.

Explanation

A fair test changes only the independent variable and keeps every other factor the same. Using many plants of one species, splitting them into fertilized and unfertilized groups, and holding light and water equal controls other variables. Repeating across several plants also reduces the effect of chance differences.

Question 6Scientific Inquiry and Process Skills

Which instrument would a student choose to measure the volume of a small irregular stone most directly?

  1. A graduated cylinder partly filled with water Correct answer.
  2. A thermometer
  3. A metric ruler
  4. A beam balance

Explanation

An irregular solid has no simple formula for volume, so displacement is used. Dropping the stone into water in a graduated cylinder raises the water level by an amount equal to the stone's volume. A ruler works only for regular shapes, and a balance measures mass.

Question 7Scientific Inquiry and Process Skills

A student predicts that a ball will roll farther down a steeper ramp. Which result would support the prediction?

  1. The ball does not roll on any ramp.
  2. The ball rolls the same distance on every ramp.
  3. The ball rolls farthest on the steepest ramp. Correct answer.
  4. The ball rolls farthest on the gentlest ramp.

Explanation

A prediction is supported when the data match the expected pattern. If steeper ramps cause longer rolls, the steepest ramp should give the greatest distance. Data showing no difference or the opposite pattern would count against the prediction.

Question 8Scientific Inquiry and Process Skills

A scientist repeats an experiment five times and gets nearly identical results each time. What does this most directly suggest?

  1. The measurements are accurate.
  2. The experiment had no variables.
  3. The results are reliable. Correct answer.
  4. The hypothesis is proven true forever.

Explanation

When repeated trials give consistent results, the data are reliable, meaning the same outcome can be expected again. Reliability does not by itself guarantee accuracy, because a repeated mistake can be consistent. No single experiment proves a hypothesis permanently.

Question 9Scientific Inquiry and Process Skills

Which of these is the best example of an inference rather than an observation?

  1. The beaker contains 50 mL of clear liquid.
  2. The liquid is water because it boils at 100 degrees Celsius. Correct answer.
  3. The liquid in the beaker is boiling.
  4. The thermometer reads 100 degrees Celsius.

Explanation

An observation is information gathered directly with the senses or instruments, while an inference is a logical conclusion drawn from that information. Identifying the liquid as water from its boiling point is a conclusion based on evidence. Volume, boiling, and temperature readings are direct observations.

Question 10Scientific Inquiry and Process Skills

A bar graph is best used to display which kind of data?

  1. How one plant's height changed each day for a month
  2. The steps of the water cycle in order
  3. Counts of students who chose each of four favorite sports Correct answer.
  4. The exact path a runner took through a park

Explanation

A bar graph compares separate categories or counts, and bars do not suggest a continuous connection between them. Counts of students choosing each sport are discrete categories, so bars suit them well. Continuous change over time is better shown by a line graph.

Question 11Scientific Inquiry and Process Skills

A student tests how the length of a pendulum affects the time for one swing. Which variable should be kept constant?

  1. The mass of the bob Correct answer.
  2. The length of the string
  3. The time for one swing
  4. The number of swings counted

Explanation

In a fair test only the independent variable changes while everything else is held constant. Here string length is being changed and swing time is the measured outcome, so the bob's mass must stay the same. Otherwise mass differences could explain any change in swing time.

Question 12Scientific Inquiry and Process Skills

A student writes, 'Plants grow taller when given more water.' Which observation would count as evidence against this statement?

  1. Plants given more water were greener than plants given less.
  2. Plants given more water grew the same or shorter than plants given less. Correct answer.
  3. Plants given more water grew taller than plants given less.
  4. Plants given more water were measured with a ruler.

Explanation

Evidence against a claim must contradict the predicted relationship. If extra water produced no height gain or a height loss, the claim that more water means taller plants fails. Greenness and the choice of measuring tool do not address the height prediction.

Question 13Scientific Inquiry and Process Skills

Which of these questions can be answered by a scientific investigation?

  1. Which color of backpack is the most fashionable?
  2. Does the color of light affect how quickly a plant's leaves grow? Correct answer.
  3. Should students be allowed to choose their own seats?
  4. Is vanilla the tastiest flavor of ice cream?

Explanation

A scientific question must be answerable with measurable evidence gathered through testing. Leaf growth under different light colors can be measured and compared. Questions about fashion, fairness of rules, and tastiness depend on personal opinions that instruments cannot settle.

Question 14Scientific Inquiry and Process Skills

A student measures the length of a pencil as 17.2 cm, 17.3 cm, and 17.2 cm. Which statement about the data is most reasonable?

  1. The measurements show a clear trend over time.
  2. The measurements are consistent and close to one another. Correct answer.
  3. The measurements prove the pencil is exactly 17.2 cm.
  4. The measurements are all incorrect because they differ.

Explanation

Repeated readings that differ by only a tenth of a centimeter are tightly grouped, which indicates good precision. Small differences are expected from reading uncertainty and are not errors by themselves. Three trials cannot prove an exact value, only support a best estimate.

Question 15Scientific Inquiry and Process Skills

Which step should come first when carrying out a scientific investigation?

  1. Repeating the experiment several times
  2. Writing a clear question and planning a procedure Correct answer.
  3. Recording the final results in a table
  4. Drawing a conclusion from the data

Explanation

Scientific investigations begin with a focused question and a planned procedure that describes how evidence will be gathered. Conclusions, data tables, and repeated trials all come after the plan is set. Without a clear question, the later steps have nothing to organize around.

Question 16Scientific Inquiry and Process Skills

A student wants to compare the strength of two brands of paper towel. Which procedure gives the most useful comparison?

  1. Weigh the rolls of each brand on a balance.
  2. Ask classmates which brand they prefer.
  3. Use each brand once with different amounts of water.
  4. Test each brand several times with the same amount of water and the same size sheet. Correct answer.

Explanation

A useful comparison holds all factors constant except the brand being tested and repeats trials to reduce chance effects. Using equal water amounts and equal sheet sizes isolates the towel's strength as the cause of any difference. Single trials and opinion surveys do not measure strength.

Question 17Scientific Inquiry and Process Skills

A graph shows that as the temperature of a solvent rises, the time needed for sugar to dissolve decreases steadily. What relationship does the graph show?

  1. Temperature and dissolving time both increase together.
  2. Dissolving time has no connection to temperature.
  3. Higher temperature is linked to shorter dissolving time. Correct answer.
  4. Lower temperature always makes sugar dissolve faster.

Explanation

The graph shows an inverse relationship: as one variable rises, the other falls. Higher temperatures correspond to less time needed for the sugar to dissolve. Describing the pattern correctly is the first step toward explaining why the relationship exists.

Question 18Scientific Inquiry and Process Skills

Why do scientists usually share their methods and results with other scientists?

  1. So the results can be kept secret from the public
  2. So other scientists can repeat the work and check the findings Correct answer.
  3. So the experiment never has to be repeated
  4. So the hypothesis can be changed without evidence

Explanation

Sharing methods lets other researchers repeat an investigation and see whether they get the same results. This checking process, called peer review and replication, strengthens confidence in scientific claims. Science depends on open evidence rather than secrecy or untested claims.

Question 19Scientific Inquiry and Process Skills

A student claims that plants grow better when music is played because the plants near the speaker were tallest. What is the main weakness of this conclusion?

  1. The plants near the speaker may have received more light or warmth as well. Correct answer.
  2. Music cannot be measured with instruments.
  3. Plant height is impossible to measure accurately.
  4. The student used plants instead of animals.

Explanation

A valid conclusion requires that only the tested factor differ between groups. If plants near the speaker also got more light or heat, those factors could explain the height difference instead of the music. Other variables must be controlled before cause can be claimed.

Question 20Scientific Inquiry and Process Skills

A table lists four trials of a cart rolling down a ramp: 2.1 s, 2.0 s, 2.2 s, and 2.1 s. What is the best estimate of the typical time?

  1. 2.2 s, the highest value
  2. 2.1 s, the value that appears most often and sits in the middle Correct answer.
  3. 4.2 s, the sum of the first and last values
  4. 2.0 s, the lowest value

Explanation

When trials cluster closely, the middle value or the mean gives the best estimate of the typical result. Here the readings center on about 2.1 s. Choosing only the highest or lowest value ignores the rest of the data.

Question 21Scientific Inquiry and Process Skills

Which statement describes a scientific model?

  1. A guess made without any evidence
  2. A final answer that can never be changed
  3. A list of steps followed in every experiment
  4. A simplified representation used to explain or predict how something works Correct answer.

Explanation

Models are simplified versions of real systems, such as diagrams or physical objects, that help scientists explain observations and make predictions. Because they are simplified, models are revised when new evidence appears. They are not permanent answers or baseless guesses.

Question 22Scientific Inquiry and Process Skills

A student measures the mass of a sample three times and gets 5.0 g, 5.0 g, and 5.0 g, but the balance was not zeroed before use. What is the most likely problem?

  1. The data are random and cannot be trusted at all.
  2. The data are precise but may be inaccurate because of a systematic error. Correct answer.
  3. The data are accurate because all readings agree.
  4. The data show that the sample's mass changed during the trials.

Explanation

An unzeroed balance shifts every reading by about the same amount, which is a systematic error. Repeated readings will still agree closely with one another, so they look precise, yet all may be offset from the true mass. Agreement alone cannot rule out such a consistent error.

Question 23Scientific Inquiry and Process Skills

Which unit is appropriate for reporting the mass of a small rock?

  1. Degrees Celsius
  2. Grams Correct answer.
  3. Liters
  4. Seconds

Explanation

Mass is measured in grams or kilograms, so grams suit a small rock. Liters measure volume, degrees Celsius measure temperature, and seconds measure time. Matching the unit to the quantity being measured keeps data meaningful.

Question 24Scientific Inquiry and Process Skills

Two students test whether salt water freezes more slowly than fresh water. Student A uses a freezer set at -5 degrees Celsius; Student B uses a freezer set at -18 degrees Celsius. Why can their results not be fairly compared?

  1. Fresh water always freezes before salt water.
  2. The freezer temperatures differ, so temperature could explain any difference in freezing time. Correct answer.
  3. Freezing time cannot be measured with a clock.
  4. Salt water cannot be frozen in any freezer.

Explanation

To compare two groups fairly, every factor except the one being tested must be the same. If the freezers are at different temperatures, the colder one will speed freezing regardless of salt. The comparison is therefore confounded by temperature.

Question 25Scientific Inquiry and Process Skills

A student wants to know whether the height of a dropped ball affects how high it bounces. Which data table would best organize the investigation?

  1. A table listing only the highest bounce ever seen
  2. A table with drop height and matching bounce height for several trials Correct answer.
  3. A table of the time of day each trial was done
  4. A table of the ball's color and its mass

Explanation

A useful data table records the independent variable next to the dependent variable so the relationship can be seen. Drop height and bounce height belong in matched columns for each trial. Color, mass, or time of day do not answer the question being asked.

Question 26Scientific Inquiry and Process Skills

A student wants to find out whether a paper clip sinks faster in warm water or in cold water. Which plan is the best scientific test?

  1. Drop the same paper clip into one cup of warm water and one cup of cold water, and time each drop. Correct answer.
  2. Drop the paper clip into warm water, then into cold water, using a different cup size each time.
  3. Drop a large paper clip into warm water and a small paper clip into cold water, and time each drop.
  4. Drop the same paper clip into warm water twice and into cold water once.

Explanation

A fair test changes only the factor being studied, which here is water temperature, and keeps everything else the same. Using the same paper clip, equal cups, and the same drop height means any difference in sinking time can be credited to temperature. Timing each trial also gives measurable evidence rather than a guess.

Question 27Scientific Inquiry and Process Skills

A student records that a candle burned for 45 minutes in a jar with no lid and for 12 minutes in a sealed jar. Which conclusion is best supported by these data?

  1. The candle in the sealed jar was made of a different wax.
  2. Candles always burn longer when they are larger.
  3. A sealed jar prevents the candle from burning as long. Correct answer.
  4. Burning time depends only on the color of the jar.

Explanation

The only factor changed between the two trials was whether the jar was sealed, and the sealed trial ended much sooner. A conclusion should stay within what the data show, so the safe claim is that sealing the jar shortened burning time. Explaining why would require further testing, such as measuring the air inside the jar.

Question 28Scientific Inquiry and Process Skills

A class measures the boiling point of water four times and gets 98 degrees Celsius, 99 degrees Celsius, 97 degrees Celsius, and 98 degrees Celsius. The accepted value is 100 degrees Celsius. Which statement best describes these results?

  1. They are neither accurate nor precise.
  2. They are both accurate and precise.
  3. They are accurate but not precise.
  4. They are precise but not accurate. Correct answer.

Explanation

Precision describes how closely repeated measurements agree with one another, while accuracy describes how close they are to the true value. These readings cluster tightly together, so they are precise, but all fall below 100 degrees Celsius, so they are not accurate. A systematic error such as a misread thermometer could explain the consistent low values.

Question 29Scientific Inquiry and Process Skills

A student claims that a fertilizer makes bean plants grow taller. Which evidence would most strongly support this claim?

  1. The fertilized plants were kept in a warmer room than the unfertilized plants.
  2. A single fertilized plant grew taller than a single unfertilized plant.
  3. The student read in a gardening book that fertilizer helps plants grow.
  4. Twenty fertilized plants grew taller on average than twenty unfertilized plants grown under the same conditions. Correct answer.

Explanation

Strong support comes from many trials in which only the fertilizer differs and all other conditions are matched. A large sample with a clear average difference makes the result less likely to be due to chance. Evidence must also come from the student's own fair comparison, not from prior belief.

Question 30Scientific Inquiry and Process Skills

A student measures the mass of a sample as 12.4 grams, 12.5 grams, and 12.4 grams, and reports the result as 12.4 grams. Which statement about this report is most reasonable?

  1. The report should list all three readings as separate final results.
  2. The report is reasonable because the readings are close together and the average rounds to about 12.4 grams. Correct answer.
  3. The report should have been rounded to 12 grams to show it is an estimate.
  4. The report is wrong because the average of the three readings was not used.

Explanation

When repeated readings agree closely, their average gives the best single estimate of the quantity measured. The mean of 12.4, 12.5, and 12.4 grams is about 12.43 grams, which rounds to 12.4 grams at the precision of the balance. Reporting one representative value is standard practice as long as the trials are consistent.

Question 31Life Science: Organisms and Ecosystems

Which structure in a plant cell captures light energy and uses it to make food?

  1. Vacuole
  2. Mitochondrion
  3. Chloroplast Correct answer.
  4. Cell membrane

Explanation

Chloroplasts contain the green pigment chlorophyll, which absorbs light energy so the plant can carry out photosynthesis and build sugars from carbon dioxide and water. Other organelles do not perform this light-capturing role.

Question 32Life Science: Organisms and Ecosystems

A rabbit eats grass, and a fox eats the rabbit. In this food chain, what role does the rabbit play?

  1. Secondary consumer
  2. Primary consumer Correct answer.
  3. Decomposer
  4. Producer

Explanation

A consumer that eats a producer is a primary consumer, so the grass-eating rabbit sits at the first consumer level. The fox, which eats the rabbit, is the secondary consumer.

Question 33Life Science: Organisms and Ecosystems

Which of these organisms is a vertebrate?

  1. Snail
  2. Earthworm
  3. Beetle
  4. Frog Correct answer.

Explanation

Vertebrates are animals with a backbone and an internal skeleton, and frogs belong to this group. Earthworms, snails, and beetles are invertebrates because they lack a backbone.

Question 34Life Science: Organisms and Ecosystems

What is the main reason living things need a continuous supply of energy?

  1. To make their bodies heavier over time
  2. To prevent water from entering their cells
  3. To carry out life processes such as growth and movement Correct answer.
  4. To increase their body temperature above the surroundings

Explanation

Energy released from food powers essential life processes, including growth, repair, movement, and keeping internal conditions stable. Without a steady energy supply these processes would stop and the organism could not survive.

Question 35Life Science: Organisms and Ecosystems

Which feature best describes an inherited characteristic?

  1. A scar a person gets from a fall
  2. Eye colour passed from parents to offspring Correct answer.
  3. A skill practised until it improves
  4. A language a child learns at school

Explanation

Inherited characteristics are features passed from parents to offspring through genetic material, and eye colour is a classic example. Learned behaviours and injuries acquired during life are not inherited.

Question 36Life Science: Organisms and Ecosystems

Which group of animals has feathers and lays eggs with hard shells?

  1. Birds Correct answer.
  2. Fish
  3. Amphibians
  4. Reptiles

Explanation

Birds are the only animal group with feathers, and they reproduce by laying eggs with hard shells. Fish, amphibians, and reptiles do not have feathers.

Question 37Life Science: Organisms and Ecosystems

In a pond ecosystem, which organism is a producer?

  1. Water flea
  2. Small fish
  3. Pond snail
  4. Green algae Correct answer.

Explanation

Producers make their own food using light energy, and green algae carry out photosynthesis in the pond. The animals listed must eat other organisms to obtain energy.

Question 38Life Science: Organisms and Ecosystems

A student finds a green plant growing towards a window. Which life process does this best show?

  1. Excretion
  2. Respiration
  3. Reproduction
  4. Response to stimuli Correct answer.

Explanation

Living things respond to changes in their surroundings, and a plant bending towards light is a clear response to a stimulus. This light-seeking growth helps the plant capture more energy for photosynthesis.

Question 39Life Science: Organisms and Ecosystems

In a food web, a hawk eats snakes, and the snakes eat mice, which eat seeds. If the mouse population suddenly falls, what is the most likely short-term effect?

  1. The hawk population will increase at once
  2. The seed population will immediately disappear
  3. The snake population will decrease because food is scarcer Correct answer.
  4. The snakes will start making their own food

Explanation

Each predator depends on the level below it for food, so fewer mice means less food for snakes and their numbers are likely to fall. Changes at one level of a food web ripple through the levels above and below it.

Question 40Life Science: Organisms and Ecosystems

Which statement correctly compares respiration and photosynthesis in a plant?

  1. Both processes absorb carbon dioxide from the air
  2. Photosynthesis happens only at night, while respiration happens only in the day
  3. Both processes release oxygen as a waste product
  4. Respiration releases energy from food, while photosynthesis stores energy in food Correct answer.

Explanation

Photosynthesis uses light energy to build food molecules, storing energy in them, while respiration breaks those molecules down to release usable energy. The two processes use opposite inputs and outputs.

Question 41Life Science: Organisms and Ecosystems

Why does a population of bacteria on a petri dish eventually stop growing even when food is still present?

  1. The bacteria stop reproducing once they can see each other
  2. Bacteria turn into viruses when crowded
  3. Waste products build up and space or resources become limited Correct answer.
  4. The dish absorbs all the bacteria

Explanation

Population growth is limited by factors such as accumulating toxic waste, crowding, and the depletion of resources. When these limits are reached, births no longer outnumber deaths and growth levels off.

Question 42Life Science: Organisms and Ecosystems

A cactus has thick, fleshy stems and leaves reduced to spines. Which benefit do the spines provide?

  1. They reduce water loss and discourage plant-eating animals Correct answer.
  2. They attract more insects for pollination
  3. They store large amounts of water for the plant
  4. They absorb nutrients directly from the air

Explanation

Spines are modified leaves with a very small surface area, which limits water loss through transpiration, and they also deter animals that might eat the plant. These adaptations suit a dry environment.

Question 43Life Science: Organisms and Ecosystems

Which sequence correctly shows energy flow through a simple food chain?

  1. Snake, frog, grasshopper, grass, sunlight
  2. Grass, sunlight, frog, grasshopper, snake
  3. Sunlight, grass, grasshopper, frog, snake Correct answer.
  4. Frog, grass, snake, sunlight, grasshopper

Explanation

Energy enters most food chains as sunlight, is captured by producers such as grass, and then passes to each consumer in turn. The arrows of energy flow follow the order in which organisms eat one another.

Question 44Life Science: Organisms and Ecosystems

Two plants of the same species are grown in identical pots; one is watered daily, the other every ten days. Both get the same light. What is the independent variable in this experiment?

  1. Type of soil used
  2. Amount of light received
  3. Height of the plants
  4. How often the plants are watered Correct answer.

Explanation

The independent variable is the factor the experimenter deliberately changes, which here is the watering frequency. Light, pot type, and soil are kept the same so that the effect on growth can be attributed to water alone.

Question 45Life Science: Organisms and Ecosystems

Which human activity is most likely to reduce biodiversity in a forest?

  1. Building nesting boxes for local birds
  2. Planting a mixture of native trees
  3. Clearing large areas of forest for farmland Correct answer.
  4. Setting aside land as a protected reserve

Explanation

Biodiversity is reduced when habitats are destroyed, because many species lose the places where they feed, breed, and shelter. Large-scale forest clearance removes these habitats and can drive populations to local extinction.

Question 46Life Science: Organisms and Ecosystems

Which statement about a decomposer such as a fungus is correct?

  1. It competes with plants for sunlight
  2. It makes its own food using sunlight
  3. It is always the first organism in a food chain
  4. It breaks down dead material and returns nutrients to the soil Correct answer.

Explanation

Decomposers break down dead plants and animals and release nutrients back into the soil, where producers can use them again. This recycling keeps nutrients available within the ecosystem.

Question 47Life Science: Organisms and Ecosystems

A change in a predator population is often followed by a change in the prey population. Which pattern best describes this relationship?

  1. Prey numbers are unaffected by predators
  2. Prey numbers rise forever while predators fall forever
  3. Predator numbers always stay exactly the same
  4. Predator and prey numbers rise and fall in a repeating cycle Correct answer.

Explanation

Predator and prey populations influence each other in a repeating cycle: more prey allows predators to increase, and more predators then reduce the prey, which in turn limits the predators. This feedback produces regular rises and falls.

Question 48Life Science: Organisms and Ecosystems

Which feature helps a fish survive in water but would be a disadvantage on land?

  1. A backbone supporting the body
  2. Eyes that detect movement
  3. A mouth for taking in food
  4. Gills for taking oxygen from water Correct answer.

Explanation

Gills are thin, moist structures that absorb dissolved oxygen from water, and they collapse and dry out when exposed to air. This makes them well suited to water but unsuitable for breathing on land.

Question 49Life Science: Organisms and Ecosystems

Which two organisms in a woodland are most likely to compete directly for the same food?

  1. A fox and a mushroom growing nearby
  2. A squirrel and a woodpecker that both eat insects and nuts from trees Correct answer.
  3. An owl and a mouse it hunts
  4. A fern and a deer that eats the fern

Explanation

Competition occurs when two organisms need the same limited resource, and two animals feeding on the same insects and nuts in the same trees overlap strongly. A predator and its prey, or a plant and its eater, have different roles rather than competing for the same food.

Question 50Life Science: Organisms and Ecosystems

Which statement best explains why a food chain rarely has more than five levels?

  1. Higher-level consumers cannot digest plants
  2. Only a small fraction of energy passes to the next level, so little remains Correct answer.
  3. Animals at each level are always larger than those below
  4. Producers cannot support more than four consumers

Explanation

At each feeding step most energy is used for life processes or lost as heat, so only a small share is stored in the consumer's body. After several transfers too little energy remains to support another level.