Which of the following is used as evidence in supporting the idea that life changes over time?

a. the time period in which an embryo develops

b. the similarities in the body systems such as the nervous and circulatory systems

c. the existence of homologous structure

d. the big bang theory

The answer to this question would be choice C. the existence of homologous structures

Explanation: Basically, homologous structures are structures that are similar to each other, but are found in different organisms (or animals). In other words, they are structures in common between species. Moreover, this homologous structures basically show that organisms come from a common ancestor and have changed over time.