Free-Response Strategy

Decode the command verbs.

Most lost FRQ points come from misreading the verb. Below: every verb the AP rubric uses, what it actually demands, and how graders score it.

The verb list

IDENTIFY / STATE

What it means: Provide the name or specific answer.

How to score: One concise word or phrase. No explanation needed.

Example: "Identify the molecule that serves as the final electron acceptor." → "Oxygen (O₂)."

DESCRIBE

What it means: Provide relevant features of a topic.

How to score: A few sentences. Include detail, but no causal reasoning required.

Example: "Describe the structure of the inner mitochondrial membrane." → folded into cristae, embedded ETC complexes & ATP synthase, impermeable to H⁺.

EXPLAIN

What it means: Show why or how with a logical chain.

How to score: "Because X, then Y." Cause → effect. Most missed verb — students often only describe.

Example: "Explain why cyanide blocks ATP production." → "Cyanide inhibits complex IV, so electrons cannot reach O₂; the H⁺ gradient collapses; ATP synthase has no driving force."

JUSTIFY

What it means: Support a claim with evidence and reasoning.

How to score: Connect data/evidence to the claim. Use phrases like "this is supported by …"

Example: "Justify that the population is undergoing genetic drift." → cite small N, random allele frequency change unrelated to fitness.

PREDICT

What it means: State an expected outcome based on given information.

How to score: Pair with reasoning if asked ("predict and explain"). Use future tense.

Example: "Predict the effect of removing CO₂ from the chloroplast." → Calvin cycle stops; ATP/NADPH accumulate; light reactions slow.

CALCULATE

What it means: Show numerical work.

How to score: Always show formula → substituted values → final number with units. Even if you stumble, partial credit lives in the work.

Example: "Calculate Ψs of 0.4 M NaCl at 25 °C." → Ψs = −iCRT = −(2)(0.4)(0.0831)(298) = −19.81 bars.

CONSTRUCT / DRAW

What it means: Make a graph or diagram.

How to score: Title, labeled axes with units, appropriate scale, plotted data, line/curve. Bar graph for categorical data; line/scatter for continuous.

Example: "Construct a graph of dissolved O₂ vs. depth." → titled, depth on x with units, O₂ on y, smooth curve.

EVALUATE

What it means: Judge the validity or strength of an argument or method.

How to score: Take a position; back it with evidence. State limitations.

Example: "Evaluate the conclusion drawn from the data." → identify confounds, sample size, replication.

SUPPORT A CLAIM

What it means: Use evidence + reasoning to back a stated claim.

How to score: Treat as JUSTIFY. Reference specific data points or known mechanisms.

MAKE A CLAIM

What it means: State a specific position.

How to score: One concise sentence. Avoid hedging.

Writing tips

  • Answer in the order asked — graders use a checklist.
  • Use scientific vocabulary precisely (don't say "the cell wants" — say "selectively favored").
  • For "describe AND explain," do both — describe earns the easy points, explain earns the upper-tier points.
  • Don't restate the prompt; jump to the answer.
  • Bullet points are acceptable but full sentences are safer.
  • On calculations: write the formula first. Setup points are independent of arithmetic.

The CALCULATE template

Every numeric FRQ should follow this structure — set-up points are independent of arithmetic.

1. Write the formula: Ψs = −iCRT
2. List values with units: i = 1, C = 0.4 M, R = 0.0831 L·bar/(mol·K), T = 295 K
3. Substitute: Ψs = −(1)(0.4)(0.0831)(295)
4. Final answer with units: Ψs = −9.81 bars