Which species is the first to do poorly when the environmental conditions change?
a. Indicator
b. Exotic
c. None of these choices
d. Keystone
e. Import
a
You might also like to view...
A research lab is trying to produce new antibiotics. They come up with drugs that detach the hydrophilic heads from the phospholipids in plasma membranes. This drug
A. would be highly toxic and completely useless for human beings-we also have plasma membranes with hydrophilic head groups! B. would be highly toxic only to bacteria, making it an excellent drug to develop and test further. Humans have a different phospholipid structure in their cell plasma membranes than bacteria. C. would generally not be toxic enough to damage Gram-negative bacteria, as their plasma membranes lie under a thick layer of peptidoglycan. D. would be highly toxic for human beings, but might be useful as a topical antibiotic skin cream. The top layer of skin cells is dead anyway, so it wouldn't matter if this damaged those cells. It could NOT be taken internally, though, by human beings.
Arteries carry
a. blood away from the heart. b. blood towards the heart. c. only oxygen-rich blood. d. only oxygen-poor blood. e. a combination of more than one of these
"Double fertilization" produces nutrient tissue by the union of ____
a. two egg nuclei and one sperm nucleus b. two sperm nuclei and one egg nucleus c. two sperm nuclei and two egg nuclei d. one sperm nucleus and endosperm mother cell nuclei e. two sperm nuclei and one endosperm mother cell nucleus
Pyramids often are used to show the relative amount of energy that each organism in the next higher level can obtain from the lower-level organism. Which organisms in this food web would make up the lowest level of the pyramid?
A) killer whale B) small animals C) leopard seal, elephant seal, crabeater seal D) algae