Answer:
A
Step-by-step explanation:
Almost all embryos of vertabrites look the same at early embryo stages, even humans to other organisms. This is because they all have a common ancestory, adn orginated from a organism with an embryo that looked like this.
It is clear it cannot be the other answers for the folowing reasons:
The organisms will definatly not look the same, considering they are birds and reptiles. The 2nd answer speaking of geography isnt very accurate, and cannot be determined because as I said above, any vertibrate embro looks very similar, and close geopgraphy isnt what made them look similar.
Again, all vertabrites have the same embryos, and that is a phylum. Not a genus. There are many genus in a phylum, and the ecaxt one cannot be determines.
As I said above, HUMANS look simiar to BIRDS and REPTILES, but clearly grow to be much different.
Answer:
A: the organisms share a common ancestory
These thoughs and facts hopefully answer you question, hope it helps!