What is the function of the valves in veins in the legs?
A. More blood moves through arteries.
B. They prevent blood from moving up toward the head.
C. More blood moves through veins.
D. They prevent blood from moving down toward the feet

The blue particles in this image are able to cross the cell membrane through simple diffusion. how will they be transported? outside the cell inside the cell o a. the substances will move directly across the membrane from outside the cell to inside the cell. b. the substances will move through channels in the membrane proteins from outside the cell to inside the cell. o c. the substances will move through channels in the membrane proteins from inside the cell to outside the cell. o d. the substances will move directly across the membrane from inside the cell to outside the cell.

When rutherford performed his metal foil experiment, he was surprised that most of the alpha particles

Which of these would most likely be a stimulus that would cause the body to initiate feedback mechanisms a.) normal body temperature in an arctic environment b.) normal boy temperature in a tropical environment c.)light physical activity d.)low blood sugar