Search:

Well yeah but we're only on about animals at the poles, so all the living things there do have an internal body temperature.

Gasses have a higher energy per particle than solids or liquids, and so when they are in a room with lots of space the particles move to occupy all of the space.
This is called Diffusion or...

A solution that contains as much of a dissolved substance that it can. Any more added will not dissolve unless you change the temperature.

I don't know how to answer that because I don't know what level the boy is already at. A good idea might be to let him pick himself.

Is this about using limewater to test for carbon dioxide?
You aren't very clear.
If you bubble carbon dioxide through Limewater it will turn cloudy, the more cloudy it goes the more concentrated...

Gravity would be my guess too.
Or a magnetic field.

Xiphias: it's a swordfish

You can get hot and cold deserts. Something is a desert if it has under a certain amount of rainfall a year.
Mountains are cold because they have a high altitude. And for every 100m above sea level...

Gas

Because living things have an internal body temperature that keeps them warm. Therefore their bodies don't get cold enough to allow the blood to freeze.

I think it's Eddie Money, (Let's be lovers is the name of the song you're right)