Explain why chances of nose bleeding increase with altitude in humans

Although the two theories differ on the evolutionary path of dinosaurs, they agree that

Which of the following sex and generation combinations directly produces the pollen tube of angiosperms? a) male gametophyteb) female gametophytec) male sporophyted) female sporophyte

What is a difference between systemic and pulmonary circulation? a. systemic circulation carries oxygenated blood to the lungs and pulmonary circulation carries deoxygenated blood to the body. b. systemic circulation carries deoxygenated blood to the lungs and pulmonary circulation carries oxygenated blood to the body. c. systemic circulation carries deoxygenated blood to the body and pulmonary circulation carries oxygenated blood to the lungs. d. systemic circulation carries oxygenated blood to the body and pulmonary circulation carries deoxygenated blood to the lungs.