Gases, like oxygen and carbon dioxide, move across cell membranes using simple diffusion. When ions can pass through the membrane without the aid of other molecules, and since oxygen and carbon dioxide can pass through the membrane, it is known as simple diffusion.
Biological diversity, food production, average global surface temperature and carbon dioxide concentrations in the atmosphere
N an experiment the "control" is the group of people or object this is used to measure the effect of the variable. The "control" is the thing that does not change and is not the thing in question.
In an experiment the "variable" is the thing which is changed and manipulated by the experimenter. It is the effect of something,
Example: You want to test a drug. you get a group of 40 people. 20 people are given the pill, 20 people are not given the pill but a sugar pill. the people who have the pill is the "variable" and the people who dont have the pill is the "control".
Answer:
The atmosphere is the blanket of gases which surrounds Earth. It is held near the surface of the planet by Earth's gravitational attraction.
Explanation: