Marine biologist Dr. James Estes researched sea otters and their habitats in the Aleutian Islands of the North Pacific Ocean. Sea otters feed on animals such as crabs and urchins. Islands with sea otters contained a lot of kelp, a seaweed that is an important food source for fish and other sea animals. However, Islands without otters had large populations of urchins but no kelp since sea urchins feed on this seaweed. Since sea otters are able to control the population of urchins, this allows for kelp to freely grow in those areas. Given this information, what term best describes the otter in the Aleutian Islands ecosystem?(1 point)

keystone species

Your friend John is having trouble with his compost bin. The material in his compost pile doesn’t seem to be decomposing well. You take a sample of the pile and check for the presence of microorganisms under the microscope. You see that there are indeed microorganisms; however, they don’t appear to be growing very fast. John says that he regularly mixes his compost pile to expose it to oxygen but has noticed the pile feels cold. What is the most likely explanation for this problem?(1 point)

Responses

The compost pile was sufficiently moist.
The compost pile was sufficiently moist.

The compost pile contained incorrect amounts of "greens" and "browns".
The compost pile contained incorrect amounts of "greens" and "browns".

The compost pile contained aerobic bacteria.
The compost pile contained aerobic bacteria.

The compost pile was placed in the sunshine.

The compost pile contained incorrect amounts of "greens" and "browns".