Q: Co 2 , h 2 o, methane, o 3 , nitrous oxides (no and no 2 ), and chlorofluorocarbons (cfcs) are known as what type of gases? Choices: - chemical gases - hydrogen gases - carbonate gases - greenhouse gases A:
greenhouse gases

Q: What guards the opening between the right atrium and the right ventricle? Choices: - superior vena cava - brachiocephalic trunk - aorta - tricuspid valve A:
tricuspid valve

Q: What refers to the union of a male and female of the same species for reproduction? Choices: - asexual reproduction - dating - behavior - mating A:
mating