Average heights of American men and women have increased steadily since the 1940s.The best explanation for this observation is that height is
A) a polygenic trait.
B) influenced by an X-linked gene.
C) influenced by environmental changes like improvements in diet.
D) influenced by a Y-linked gene.
E) influenced by crossing over.

Question

Quizplus · Accepted Answer

The effects of gene expression can only be seen if the environment provides raw materials for that expression.

Average Heights of American Men and Women Have Increased Steadily