The graphs below show the changes in crab color at one beach. Which statement best explains the change in the number of light tan and dark tan crabs from 1950 to 1990?
a
Both light tan and dark tan body color provided an advantage to the crabs, regardless of their environment or habitat.
b
Either light tan or dark tan body color, but not both colors, provided an advantage to the crabs, regardless of their environment or habitat.
c
Both light tan and dark tan body color provided an advantage to the crabs on this beach, but not necessarily in other crab habitats.
d
Light tan body color provided an advantage over dark tan body color on this beach, but not necessarily in other crab habitats.

C. Both light tan and dark tan body color provided an advantage to the crabs on this beach, but not necessarily in other crab habitats.

Explanation:

The changes in the number of light tan and dark tan body color of crabs that occured can be described as a diversifying or disruptive selection.

This disruptive selection occurs when individuals with extreme traits on both ends of the spectrum become selected against individuals of ntermediate or medium traits.

In the case of the crab, their environment favors the selection of both extreme values as against those intermediate individuals, as both light tan and dark tan body color of the crabs gives them advantage over others in this particular environment. This may only be obtainable in this environment or similar beach environment with the same settings and conditions.