Given the fact that:  As the rocks move deeper into the Earth, temperature and pressure increase.  Answer the question:   When we look deep into the earth through a volcano the temperature decreases or increases?
increases

Given the fact that:  The forest habitat of elephants has also decreased in size due to humans moving in, so the numbers of the elephants have decreased.  Answer the question:   Erin was going to see the elephants in the jungle. If the jungle is larger than it was 20 years ago, then what has likely happened to the population of the elephants it has decreased or it has increased?
it has increased

Given the fact that:  If salt is added to a volume of water, there are more molecules in the same volume, so the water is denser.  Answer the question:   When water loses salt the water becomes more dense or less dense?
less dense