The image below represents two waves X and Y, traveling to the same medium at the same speed how are the two waves different?

D is right

Explanation:   It seems both waves have same wavelength.

Because speed = wavelength · frequency  (v = λf)  and

f = v/λ, so frequency is same.  Because period T = 1/ frequency, also periods are same.  Wave Y has higher amplidude and its energy is greater.

not sure if this what   you'r looking for would be percent composition

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds