What keeps blood from flowing back into a chamber of the heart

Which of these is a sexual stereotype? a) on average, males are taller than females. b) people over the age of 60 are not interested in sex. c) male hormone levels differ from those of females. d) there are more male representatives than female representatives in congress.

The heart and lung are located in which cavity ? thoracic

Where are teens exposed to ads about tobacco products? on the radio in magazines near schools on television