According to evidence from ice layers from the Antarctic, atmospheric carbon dioxide levels have been rising
since ____.
a. the dinosaurs went extinct
b. about 10,000 years ago
c. the industrial revolution began
d. the 1970s
e. human evolved 200,000 years ago
ANSWER: c
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Which statement below does NOT correctly describe paracrine regulation?
A. Paracrine regulatory molecules include cytokines and growth factors. B. Nitric oxide can function either as a neurotransmitter or a paracrine regulatory molecule. C. Endothelin and bradykinin are paracrine molecules that control blood vessel constriction and dilation. D. Paracrine molecules are released into the circulatory system to affect distant tissues. E. Platelet-derived growth factor and insulin-like growth factor are both paracrine regulatory molecules.
Given the half-life of radioactive carbon of 5730 years, if a sample from an archaeological site is analyzed, and it is determined to have 1/4 of the amount of 14C that a living organism would have, describe how you would go about aging this fossil
What will be an ideal response?
Heirloom plants are treasured for their flavorful produce and true-breeding progeny that allow gardeners to avoid repeatedly purchasing seed from agribusiness conglomerates. What special effort is required to save seed from heirloom biennials such as carrots?
A. Since carrots build up so much beta-carotene, they do not devote many resources to seed development. A yellow carrot variety will produce better seeds than a darker one. B. Since carrots produce large roots, they do not devote many resources to seed development. The roots must be trimmed before collecting seed. C. Biennials do not produce seed until the second year of growth. Although carrot roots are normally harvested after one season, they must be allowed to grow another year for seed collection. D. Since carrots are related to wild weeds, they are often cross-pollinated. The green top must be bagged to ensure self-pollination.
Methanotrophs affect global temperature. This is because:
A. Methanotrophs convert methane to carbon dioxide, thereby decreasing the amount of methane in the environment but increasing the amount of carbon dioxide there. Since both methane and carbon dioxide are greenhouse gases whose accumulation causes a rise in global temperature, the decrease in one cancels the increase in the other and methanotrophs have no net effect on global warming. B. Methanotrophs metabolize methane, thereby reducing the amount of methane in the atmosphere. Since methane is one of the greenhouse gases whose accumulation causes a rise in global temperature, its reduction by methanotrophs helps prevent global warming. C. Methanotrophs combine carbon dioxide and methane to form petroleum and in this way take both methane and carbon dioxide out of the atmosphere. Since both methane and carbon dioxide are greenhouse gases whose accumulation causes a rise in global temperature, the decrease in both helps prevent global warming. D. Methanotrophs convert methane to carbon dioxide and increase the amount of carbon dioxide in the atmosphere. Since carbon dioxide is one of the greenhouse gases whose accumulation causes a rise in global temperature, its production by methanotrophs contributes to global warming. E. Methanotrophs convert carbon dioxide to methane and increase the amount of methane in the atmosphere. Since methane is one of the greenhouse gases whose accumulation causes a rise in global temperature, its production by methanotrophs contributes to global warming.