The correct answer is: A. the ultraviolet rays of the sun.
The ionosphere is a region of Earth’s atmosphere that is ionized by solar radiation. It extends from about 50 to 1,000 kilometers (31 to 620 miles) above the surface of the Earth. The ionosphere is important because it reflects radio waves back to Earth, allowing long-distance radio communication. It also protects the Earth from harmful ultraviolet radiation from the sun.
The ultraviolet rays of the sun are a type of electromagnetic radiation that is harmful to humans and other living things. They can cause skin cancer and other health problems. The ionosphere absorbs most of the ultraviolet radiation from the sun, protecting us from its harmful effects.
The infrared rays of the sun are a type of electromagnetic radiation that is not harmful to humans. They are responsible for the Earth’s heat. The ionosphere does not absorb infrared radiation.
The falling meteorites are not affected by the ionosphere. They can reach the Earth’s surface and cause damage.
Therefore, the correct answer is: A. the ultraviolet rays of the sun.