The range of cattle egrets has expanded between 1937 and today. how would an ecologist likely explain the expansion of the cattle egret?

I had to look for the options and here is my

Based on the attached details about the cattle egrets, how an ecologist would explain this expansion is that, a habitat that has been not been occupied by the egrets and the native herons acquired the biotic and abiotic standards of the cattle egret transplants and their descendants. (This is based on the actual option attached to this question.)

Giga is the second highest prefix on the normal scale, the first is terra.