Make sure you post the picture of the tree, so I can answer.
Answer:
C and E
Explanation:
A wavelength, when drawn like this, is between two points in the exact same spot of the wave, but in different positions. Here, C is the middle when the wave is going "down" into the trough. The next point at this position is point E, giving us our answer.
The tundra has little variation in temperatures
The answer is d. atmosphere < leaves < roots < soil
You can classify them in what phase they are in: solid, liquid, gas
You can classify them in Sizes
You can classify them by the number of moons they have
You can classify them by distance from the sun
You can classify them all as heliocentric or orbiting/circling around the sun
You can classify them by color