Two waves travel through each other, and a crest forms with an amplitude smaller that either original waves. What has happened?

This is what I think it is, correct me if I'm wrong. Answer is stated below:

Explanation:

Destructive Interference

Two waves combine to form a wave with a smaller amplitude than either the original wave. Destructive interference can occur when the crest of one wave overlaps the trough of another wave. If the crest has a larger amplitude than the trough of the other wave, a part of it remains.

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.

i believe it is c.) 1575 j.