Question

guppies are small freshwater fish. females of this species are typically dull in color. many males of this species are brightly colored, but some males of the species are also dull. scientists are studying the effect of predation on the color of male guppies. this graph shows the data collected from examining the males in a population of guppies over eight generations. no predators were present for generation 0, but an approximately constant number of predators was present for all other generations. based on the data above, the male guppy population that decreased is: brightly colored dull colored

Explanation:

グラフを見ると、捕食者が現れてから（世代1以降）、明るい色の雄のグッピーの割合が徐々に減少しています。一方、鈍色の雄のグッピーの割合は増加しています。

Answer:

brightly colored