Answer:
Girls have two X chromosomes and boys have chromosomes (XY).
Explanation:
Girls have two X chromosomes (XX), and boys have one X and one Y chromosome (XY). Whether a baby will be a boy or a girl is determined at the time of conception.
Answer: C). A biozone can help trace the path of evolution over time.
Biozone is a stratigraphic unit which contains fossils in layers of strata existed in a particular geologic period. It is named as biozone because it depicts the number of biological taxa existed in particular strata. Therefore, the variation in features within taxonomic groups in biozones can give indication of evolution with respect to time.
I believe the answer is D. Hope this helps ;D