What are the next four numbers in the pattern below ? 3,9,7,13,11,17,15,

21, 19, 25, 23

Explanation:

The pattern seems to be to add 6, then subtract 2.

21,19,25,23

Explanation:

You are adding 6 to get the next number, than subtract 2 from the the number

well, that's easy; the answer's c, "it reduces contamination of the water and substrate of the estuary."

the atmospheric gas that forms a mild acid when dissolved in water is called carbon dioxide. the correct answer is a. 2.) chemical weathering would cause an inscription on a marble headstone to become harder and harder to read over time.