Which best describes the relationship between the circulatory system and the respiratory system?
a. the circulatory system is the transport system for the respiratory system.
b. the respiratory system is the transport system for the circulatory system.
c. the circulatory system diffuses red blood cells into the respiratory system to pick up oxygen.
d. the respiratory system transfers hemoglobin to the red blood cells of the circulatory system.

When do people generally experience rapid growth for a second time? a. between the ages of 3 and 9 b. between the ages of 9 and 12 c. between the ages of 13 and 20 d. between the ages of 25 and 29 which action occurs in the third stage of cell division? a. the nuclear material of cell is copied exactly. b. the nuclear membrane disappears. c. the cell forms two nuclei d. the nuclear material separates, with half moving to either side of the cell.