20
1. what does the term carrying capacity describe?
a) the maximum number of birth rates for a population.
b) the ability of a population to accept new immigrants.
c) the population size that the environment can sustain.
d) the ratio of birth rates to death rates in a population.
2. which factor is a density-dependent limiting factor on the population of a species?
a) predation
b) unusual weather
c) natural disasters
d) seasonal variation
3. which nutrient cycle is most affected by the over-use of ammonia fertilizers on commercial farms, as well as by the accumulation of waste on cattle farms and feed lots?
a) water
b) carbon
c) nitrogen
d) phosphorus

Malik formed a hypothesis that an increase in atmospheric oxygen levels by 10% would cause red-legged grasshoppers to grow larger than normal. suppose that malik performs an experiment to test his hypothesis. which of these actions would represent a scientific mistake in his experiment? a. he experiments on live grasshoppers instead of preserved ones. b. he focuses on red-legged grasshoppers instead of all kinds of grasshoppers. c. he varies the nitrogen and carbon dioxide levels in the air from one trial to the next. d. he conducts the experiment in a controlled lab setting with a lab partner. e. he measures the mass and length of his specimens at the start of each trial.