Answer:
A is the correct answer
Explanation:
the existed about 3.8to 4.0 billion years ago
The answer is the second choice: variation, overpopulation, adaptation
Answer: B. under use; it is a scarce resource.
Explanation:
Early settlers in the town of Dry Gulch drilled wells to pump as much water as they wanted from the single aquifer beneath the town. (An aquifer is an underground body of water.) As more people settled in Dry Gulch, the aquifer level fell and new wells had to be drilled deeper at higher cost.Residents of Dry Gulch have a private incentive to under use water because it is a scarce resource.
Answer:
D) Habitats for animals.
Explanation:
It depends what the question means when it says 'the changing of the rivers'. I took it as the rivers are changing size and becoming more spread out. In that case, I chose habitats.
The more water there is, the more habitat there is for sea life.
All in all, the correct answer is D).
Answer:
the heart it is because the heart beats and it goes up and down
