Answer:
A. There are similarities in the developmental stages of different species in the animal kingdom.
Step-by-step explanation:
There are similarities in the developmental stages of different organisms in the animal kingdom. Overall, these similarities are more pronounced during the earlier stages of development (i.e., zygote through embryo) than in the later stages (i.e., fetal).
By comparing developmental stages of organisms (and by examining and interpreting fossils), information can be gained about relationships among living organisms and those that inhabited Earth in the past. This information is often used to modify and clarify existing classification systems. By studying embryological development, scientists hope to gain a better understanding of how different animal species have changed over time and how closely they are related to one another.
That, and I got it right on Study Island.