Something that is constant and does not change.

Controlled variable, if you're talking about scientific variables in experiments. (if not, you can just ignore this.)

Explanation:

Main types of variables are: Independent, Dependent, and controlled.

Independent variable is what is being changed in each experiment by the scientist.

Dependent variable is the change in result of the independent variable.

Controlled variable is other factors that have to remain constant in order for the experiment to remain valid.

For example:

Joshua wants to know how the location of a plant affects it's growth rate. He sets up 3 same plants in different locations in his classroom, and records how much they grow by after a month.

Plant A: On a desk in the middle of the room

Plant B: on a windowsill

Plant C: in a closet

The results are as follows:

Plant A grew by 1.3 inches

Plant B grew by 2 inches

Plant C grew by .5 inches

The independent variable in this experiment is the location in the room. The dependent variable is the growth rate.

The controlled variable is everything else: the type of plant, the type of soil, etc.

hope this helped!

humans can cause extinction of a species through overharvesting, pollution, habitat destruction, introduction of invasive species (such as new predators and food competitors), overhunting, and other influences. explosive, unsustainable human population growth is an essential cause of the extinction crisis.

explanation:

i didn't have the answer choices , but i tried my best.

9.9 years

a = p(1 + rt) . . account balance after time t at rate r starting with principal p

3000 = 2500(1 + 0.0202t) . . filling in the given numbers

1.2 = 1 + 0.0202t . . divide by 2500

0.2 = 0.0202t . . . subtract 1

0.2/0.0202 = t ≈ 9.901

it will take about 9.9 years for the account balance to reach $3000.