Which statements describe aspects of the relationship between sleep deprivation and drug abuse? select the two correct answers.

a. drug abuse usually reduces sleep problems.
b. drug abuse can lead to insomnia and further drug abuse.
c. sleep deprivation can increase a teen's chance of drug abuse.
d. sleep deprivation and drug abuse are not related.

Check all that occur during ventricular systole. a. the av valves open to allow blood to enter the ventricles from the atria. b. the av valves open to allow blood to enter the ventricles from the atria. c. the semilunar valves remain closed throughout systole to prevent backflow of blood into the ventricles. d. the semilunar valves remain closed throughout systole to prevent backflow of blood into the ventricles. e. the semilunar valves open to allow blood to flow into the large arteries. f. the semilunar valves open to allow blood to flow into the large arteries. g. the av valves close to prevent backflow of blood into the atria.