When a population is at its carrying capacity...

The birth rate equals the death rate so the population size stays constant.
The birth rate is at its maximum so the population stays at a high level.
The birth rate goes to zero and the population stays constant.
The death rate goes to zero so the population can reach its highest level.

What is the currently accepted scientific explanation for anthropogenic global climate change?
Human activities raise greenhouse gas levels and strengthen the greenhouse effect.
The hole in the ozone layer lets in too much sunlight, warming earth
Heat escapes from engines, forest fires, machinery, power plants, etc.
Birds feed on honeysuckle berries, spreading the seeds to new places where they can sprout and grow. This relationship is an example of...
mutualism.
predation.
competition.

The sea level is _________ as a consequence of climate warming.
increasing
decreasing

Which of the following includes abiotic components?
Species
Populations
Communities
Ecosystems

Which human activity has the major effect of increasing carbon dioxide levels in the atmosphere?
Damming rivers
Fertilizer use
Burning fossil fuels
Sewage disposal

Which human activity has the major effect of increasing carbon dioxide levels in the atmosphere?
Damming rivers
Fertilizer use
Burning fossil fuels
Sewage disposal
Pumping groundwater

Energy enters Earth's ecosystems as _________ and exits as ___________.
heat; organic matter
sunlight; carbon dioxide
sunlight; heat
heat; sunlight
Some coastal areas are more vulnerable to storms and beach erosion because mangrove forests or grass salt marshes have been cleared and removed by humans. This is most clearly an example of...
physical disturbance.
resource depletion.
pollution.
none of the above; it is not an example of environmental impact.

Which of the following communities probably is least disturbed or polluted by human activities?
A meadow with 23 native species of grass and 18 bird species
A meadow with one species of grass and no birds
A meadow with 11 native species of grass and 8 bird species

How have human activities influenced the nitrogen and/or phosphorus cycles?
Humans have not affected these cycles.
Human activities have led to storage of more nitrogen in the earth's crust.
Human activities have increased the nitrogen and phosphorus available to plants and algae.
Human activities have increased the level of phosphorus in the earth's atmosphere.
Human activities have reduced the nitrogen and phosphorus available to plants and algae.

Which of the following is abiotic?
Plants
Fungi
Rocks
All of these are abiotic
Which of the following communities has the greatest species richness?
Community A: 109 species and 22,948 total organisms
Community B: 89 species and 39,946 total organisms