In an ecosystem, there are two color varieties within a species of toads: brown and green. Over 50 years, the proportion of the population that is green increases from 20% to 50%. Which statement is the most likely to explain this change?
a
A disease caused a decrease in the proportion of brown toads.
b
The environment changed such that green toads can blend into their surroundings better.
c
Pollution caused a decrease in the proportion of brown toads.
d
The environment changed such that toads that can jump higher into the trees to survive better.