How much of the earth's animal life exists in the oceans?
80% is the answer.
The correct answer is
(1) speed
In fact, the speed of an electromagnetic wave does not depend on the type of wave, but only on the medium: since both the waves are travelling in vacuum (same medium), they are travelling at same speed, which corresponds to the speed of light in vacuum:

Without air resistance, both balls reach the ground at the same instant.
Neither horizontal motion nor weight affects vertical motion.
An atom is probably less than 1 nano-meter in size