Which describes how physical activity benefits the cardiovascular system? a. it reduces the chance of developing osteoporosis. b. it increases heart strength. c. it decreases the number of capillaries in the muscles. d. it raises blood cholesterol.

9. withdrawal occurs when alcohol is removed from the system after the brain a. adapted to the continued presence of alcohol b. become physically saturated with alcohol c. become impervious to the effects of alcohol d. begun to treat alcohol as a poison