The heart is important for transporting oxygen to the muscles when we exercise. How does the heart rate change when we go from sitting on a chair to running up the stairs? A. The heart rate stops.
B. The heart rate gets slower.
C. The heart rate gets faster.
D. The heart rate stays the same.

2. which of the following statements does not accurately describe stem cells? a. embryonic stem cells make up the inner cell mass of a blastocyst. b. with more research, stem cells may be used to repair or replace damaged cells. c. the use of stem cells is without any objections since it can be used in therapies to humans. d. adult stem cells are multipotent and can differentiate into many types of cells.

The smallest parts of these that retain their original properties are called

Which describes the changes in the earths motion?