Guard cells in plants control water pressure
The decline in the overall population of trout and larger fish is because the Insect population has decreased.
<h3>What is a population?</h3>
A population is a group of organisms of the same species living in the same habitat.
Population of organisms is affected by;
- availability of water
- space
- food and nutrients
- predators
- climate change
Since the population of trout is directly affected by the number of insect species, the decline in the overall population is because the Insect population has decreased.
Learn more about population at: brainly.com/question/746835
Natrual variations i think
Ion transport or active transport depending on which situation you have.
