Why evolution classified as a theory

The image shows ekgs of a person with normal heart waves and of a person having tachycardia. based on this image, what kind of condition is tachycardia? a. the heart beats abnormally fast. b. the heart beats abnormally slow. c. the right atrium of the heart stops working. d. the left ventricle pumps less blood to the aorta.

In order to clone adult animals, scientists typically begin with a(n)

What are two reasons for why a species might disappear from the fossil record?