Which of the following best describes a pollutant?
a. a harmful substance that is released to the environment
b. a natural substance that is used by humans or other organisms
c. a substance that is used faster than it can be replaced
d. a substance that is naturally recycled by nature

In a certain ecosystem owls are predators for mice. the owl population increases and they eat more mice this causes the mouse population to decrease what happens next? a.the birth of mice increases. b. the birth rate of owls increases c. the population of owls decreases d. the population of mice increases

Hybrid instruments that play sounds that are part sampled and part synthesized are known as:

Diagram of the evolution of land plants?