What is the answer to this question?

C

Explanation:

The temperature of an object does not change when it is going through a phase change, since there is a single specific point on the temperature gradient where that change occurs. Once the phase change has occurred, the water's temperature can continue to change in that direction, but during the phase change it does not. Hope this helps!

1 - wave length

2 - amplitude

3 - crest

4 - trough

explanation:

duh.