Question

An organism has two different possible traits, A and B. A graph of the population is shown right. Which of the following statements is true about Trait B? Check all that apply.

It decreased in frequency over time.

It became extinct.

It is carried on a recessive allele.
A graph entitled Populations for Two Traits has generation on the horizontal axis, from 0 to 80, and population in thousands on the vertical axis, from 0 to 200. Trait A begins at 90, dips slightly to 80 in generation 10, and then steadily increases to 180 for generation 80. Trait B starts at 120, and then steadily declines to 40 for generation 80.

Answer 1

Check only: "It decreased in frequency over time."

- True: the number carrying trait B falls from 120 to 40 over the generations shown.
- False: it did not become extinct — the population with trait B remains at about 40 (not zero).
- Cannot conclude: nothing in the graph tells you whether B is on a recessive or dominant allele; genetic dominance cannot be inferred from population counts alone.