An investigator who uses a cross-sectional design

A) compares people from different cultures.
B) examines a single group of people at several times as they grow.
C) examines different groups of people at the same time.
D) compares humans to other animal species.

A cross-sectional design examines different groups of people at the same time, allowing for comparisons to be made between them. Option A involves a study of people from different cultures, while option B involves examining people at different points in time. Option D involves comparing humans to other animal species, which is not related to the design of the study.