Answer:
By studying the fossil record we can tell how long life has existed on Earth, and how different plants and animals are related to each other. Often we can work out how and where they lived, and use this information to find out about ancient environments. Fossils can tell us a lot about the past.
Explanation:
Answer:
C. break down carbohydrates into glucose
Explanation:
A, B, and D are all functions of the circulatory system.
Your digestive system breaks down carbohydrates into glucose.
Answer:
AIDS
Explanation:
AIDS is the most common infectious disease causing lymphocytopenia, which arises from destruction of CD4+ T cells infected with HIV.