Science
What the Science section tests
Science questions span scientific reasoning, life science, human anatomy and physiology, chemistry, physics, and earth/space science. In reasoning items, identify the independent variable (what the experimenter changes), dependent variable (what is measured), and controlled variables (held constant). Know the difference between a hypothesis (a testable prediction), a theory (a well-supported explanation), and a law (a description of a pattern).
High-yield content: cell organelles and their functions; mitosis versus meiosis; DNA base pairing and simple Punnett squares; body systems and their roles; atoms, elements, and the periodic table; ionic versus covalent bonds; pH; speed, force, and energy; and the water cycle or rock cycle.
Traps:
- Osmosis (water across a membrane) versus diffusion (any particle down a gradient).
- Mitosis produces two identical body cells; meiosis produces four genetically varied gametes.
- Correlation is not causation; a controlled experiment needs a comparison group.
- Confusing mass and weight, or forgetting to convert units before calculating.
Worked example: Cross Bb x Bb. Each parent gives B or b with equal chance, so offspring are 1 BB : 2 Bb : 1 bb, a 3:1 dominant-to-recessive phenotype ratio.