Answer:
B. meteorites, UV rays
Step-by-step explanation:
Atmosphere of Earth acts like a protective layer around us. It also protects us from:
1. Meteoroid: These are small space rocks revolving around the Sun but cross the orbit of Earth. When the Earth crosses through such areas these rocks get attracted towards Earth due to gravity and move at a very high speed. The atmosphere prevents all the meteoroids from hitting the surface. This happens because the meteoroids get burned in the atmosphere itself due to friction. These burnt meteoroid appear like a shooting star and are called as Meteors. If some part of the rock still survives and land on Earth, it is called as meteorite. If the atmosphere was not there all small/large meteoroid would have hit the Earth.
2. UV rays: UV or ultraviolet rays are a a part of the whole EM spectrum and Sun is a major source of UV rays for us. But UV rays are harmful for us. These rays are blocked by the ozone layer of atmosphere.