TEAS Science key terms

The central point a passage is built to communicate, supported by most of its details. It is broader than any single sentence and is often stated in a topic sentence or must be inferred.

A specific fact, example, statistic, or reason that explains or proves the main idea. Details answer who, what, when, where, why, or how and can be checked against the text.

A conclusion a reader draws by combining clues in the text with prior knowledge. It is not stated directly, so it must be logical and supported by evidence from the passage.

A word, phrase, or sentence quoted or paraphrased from a passage that supports an answer or claim. Strong evidence directly relates to the question asked rather than merely sharing a topic.

The reason a writer produces a text, such as to inform, persuade, entertain, or explain a process. Purpose shapes tone, word choice, and which details are included or left out.

The writer's attitude toward the subject, conveyed through word choice and sentence structure. Tone may be objective, critical, humorous, or urgent, and differs from the reader's own reaction.

The perspective from which a text is told, such as first person, third-person limited, or third-person omniscient. It determines what information the reader can and cannot access.

The emotional or cultural association a word carries beyond its literal meaning. For example, 'thrifty' suggests approval while 'stingy' suggests disapproval, though both describe careful spending.

The literal, dictionary meaning of a word, separate from any emotional shading. It is the neutral definition shared by all speakers of the language.

The order in which events, steps, or ideas are arranged in a text. Signal words such as first, next, then, and finally help readers follow chronological or procedural order.

A text structure that examines similarities and differences between two or more subjects. Signal words include similarly, both, unlike, whereas, and in contrast.

A comparison of two quantities by division, often written as a to b, a:b, or a/b. Ratios describe a fixed relationship and can be scaled up or down while staying proportional.

An equation stating that two ratios are equal, such as 3/4 = 9/12. Proportions are solved by cross-multiplying to find an unknown value.

A rate expressed per one unit of a given quantity, such as miles per hour or cost per ounce. It is found by dividing one quantity by the other so the denominator becomes one.

A ratio that compares a number to 100, meaning 'per hundred.' To convert a decimal to a percent, multiply by 100; to convert a percent to a decimal, divide by 100.

The arithmetic average of a data set, calculated by adding all values and dividing by the number of values. It is affected strongly by unusually high or low values.

The middle value of a data set arranged in order. If there is an even number of values, the median is the mean of the two middle values.

The value that appears most often in a data set. A set may have one mode, several modes, or no mode if all values occur equally often.

The agreed sequence for evaluating expressions: parentheses and grouping symbols first, then exponents, then multiplication and division left to right, then addition and subtraction left to right.

A letter or symbol that stands for an unknown or changing number in an expression or equation. Solving usually means finding the value that makes the statement true.

A mathematical statement that two expressions are equal, joined by an equals sign. It can be solved by performing the same operation on both sides to isolate the unknown.

A systematic approach to investigation: observe, form a question, propose a hypothesis, design and run an experiment, collect data, and draw conclusions that may revise the hypothesis.

A testable, falsifiable prediction about the relationship between variables, often stated as an if-then claim. It must be supported or rejected by experimental evidence rather than opinion.

The factor the experimenter deliberately changes or manipulates between groups. It is the proposed cause, while the dependent variable is the measured effect.

The factor that is measured or observed in an experiment and is expected to respond to changes in the independent variable. It is the outcome being tested.

The comparison group in an experiment that does not receive the treatment being tested. It helps show whether observed changes are due to the treatment rather than other factors.

The selectively permeable barrier surrounding a cell that controls which substances enter and leave. It is made largely of a phospholipid bilayer with embedded proteins.

The net movement of particles from an area of higher concentration to an area of lower concentration. It requires no energy input and continues until concentrations are balanced.

The diffusion of water across a selectively permeable membrane from a region of higher water concentration to lower water concentration. It is a passive process driven by concentration differences.

Cell division that produces two genetically identical daughter cells for growth and repair. It proceeds through prophase, metaphase, anaphase, and telophase before the cytoplasm divides.

Cell division that produces four genetically varied gametes, each with half the usual chromosome number. Crossing over and independent assortment create genetic diversity in offspring.

The process by which plants, algae, and some bacteria use light energy to convert carbon dioxide and water into glucose and oxygen. It occurs mainly in chloroplasts containing chlorophyll.

The process by which cells break down glucose to release usable energy stored as ATP, producing carbon dioxide and water. Aerobic respiration requires oxygen and occurs largely in mitochondria.

Membrane-bound organelles often called the cell's powerhouses because they generate most of the cell's ATP through aerobic respiration. They contain their own DNA and have folded inner membranes.

A scale from 0 to 14 measuring hydrogen ion concentration, where below 7 is acidic, 7 is neutral, and above 7 is basic. Each whole step represents a tenfold change in acidity.

An attractive force holding atoms together, formed by sharing electrons (covalent), transferring electrons (ionic), or through metallic attraction. Bond type influences a substance's properties.

A homogeneous mixture in which a solute is evenly dissolved in a solvent. The solute is present in the smaller amount, and the mixture cannot be separated by simple filtration.

The rule that a verb must match its subject in number and person. Singular subjects take singular verbs and plural subjects take plural verbs, even when phrases separate them.

The requirement that a pronoun match the noun it refers to in number and gender. Ambiguous or mismatched references confuse readers and are common test errors.

An incomplete sentence missing a subject, a verb, or a complete thought. It is punctuated as a sentence but cannot stand alone grammatically.

Two or more independent clauses joined without correct punctuation or a conjunction. It can be fixed with a period, semicolon, or comma plus a coordinating conjunction.

A specific error in which two independent clauses are joined by only a comma. Correcting it requires a period, semicolon, or comma plus a coordinating conjunction.

A word, phrase, or clause that describes another word. A misplaced or dangling modifier appears to describe the wrong word, creating confusion or unintended meaning.

A sentence construction in which the subject performs the action, as in 'The nurse recorded the data.' It is usually clearer and more direct than passive voice.

A construction in which the subject receives the action, as in 'The data were recorded by the nurse.' It is useful when the actor is unknown or unimportant.