There is an explosion on the surface of a lake and two people John and Nil hear its sound. John is 150m away on a boat and Nil is 150m below the surface of water. Who would hear the sound first and why?

Nil

Explanation:

Sound is a wave whose speed depends on the medium it is traveling in. Sound wave travel faster in water as compared to air. In water the speed of sound wave is around 1480 m/sec whereas in air it is around 343 m/sec.

Since Nil is underwater he will hear the sound of the explosion first. But, the quality of sound will be better for John. This is because humans have evolved to listen in the air and not water. So the sound will not be clear to Nil underwater.

answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.

answer///terminator or twilight zone;