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Part 1 of 6 - 19.98/ 19.9998 Points Question 1 of 30 3.33/ 3.3333 Points Which of the following organisms excretes urea? A. Mammals B. Bony fish C. Insects D. Reptiles E. Birds Answer Key: A Feedback: Sharks, adult amphibians, and mammals usually excrete urea as their main nitrogenous waste. Question 2 of 30 3.33/ 3.3333 Points Which of the following organisms have specialized salt glands that pump salt out of their bodies? A. Sharks B. Bony fish C. Sea stars D. Sea birds E. Sea anemones Answer Key: D Feedback: Sea birds have special salt glands that pump salts out. Question 3 of 30 3.33/ 3.3333 Points A biologist is studying the excretory system of insects. Based on this information you would conclude that he or she is studying which of the following? A. Nephridia B. Flame cells C. Kidneys D. Nephrons E. Malpighian tubules Answer Key: E Feedback: A biologist is studying the excretory system of insects. Based on this information you would conclude that he or she is studying which of the following? Question 4 of 30 3.33/ 3.3333 Points What happens if humans drink sea water? A. They secrete excess salt with their salt glands. B. There is no net change in the water content of their cells. C. Their rectal glands expel excess salt. D. Their cells gain water. E. Their cells lose water. Answer Key: E Feedback: Humans have no auxiliary gland to get rid of excess salt, and the kidneys are unable to excrete salt and other solutes such as urea without also excreting water. Therefore, we need access to fresh water in order to produce enough urine to wash excess salt from the body. If we drink sea water, our cells become dehydrated as they lose water to blood, which will have a higher concentration of salts than cytoplasm. Question 5 of 30 3.33/ 3.3333 Points Because of their tendency to constantly gain water by osmosis across their gills and body structures, which of the following organisms never need to drink? A. Clams B. Marine bony fish C. Freshwater fish D. Sea anemones E. Sharks Answer Key: C Feedback: Freshwater fishes tend to gain water by osmosis across the gills and the body surface. As a consequence, these fishes never need to drink water. Question 6 of 30 3.33/ 3.3333 Points Ammonia, urea, and uric acid come from ____________ which are removed from amino acids and nucleic acids. A. Urea groups B. Protein groups C. Amino groups D. Ammonia groups E. Uric acid groups Answer Key: C Feedback: When amino acids are broken down by the body to generate energy, or are converted to fats or carbohydrates, the amino groups (NH2) must be removed because they are not needed. ... View Full Document

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