Answer:
Because Greenhouse gases let the sun's light shine onto the Earth's surface, but they trap the heat that reflects back up into the atmosphere. And this way, they act like the glass walls of a greenhouse. This greenhouse effect also keeps the Earth warm enough to sustain life.
Explanation:
Option “A” is the crest of the wave because it’s the maximum value of upward displacement within a cycle.
In gas the speed of sound is 343.2 meters per second, in liquid the speed of sound is 1,484 meters per second and in solids like steel it travels 5,120 meters per second.
