I wrote it out, sorry if it’s a little messy!
I had to look for the options and here is my answer:
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 <span>of the cattle egret transplants and their descendants. (This is based on the actual option attached to this question.)</span>
Answer:
they use it to determine whether or not the animal is related by the bone structure and the structure of the body
<span>Trophoblasts
Trophoblasts are cells that make up the external layer of a blastocyst, this is a major source of nutrient for a newly formed organism</span>