Question

The Sun’s rays are quite damaging to living organisms. Light from the Sun in outer space is composed of about 50% infrared light, 40% visible light, and 10% ultraviolet light. Small amounts of direct UV light denature DNA and kills living cells. In many laboratories, scientists use UV light to sterilize pieces of lab equipment to ensure that no living organisms remain on them.

How are living organisms able to survive on Earth despite the large amounts of radiation produced by the Sun?

Responses
A Organisms on Earth have evolved to prevent being damaged by the Sun’s radiation.Organisms on Earth have evolved to prevent being damaged by the Sun’s radiation.
B The Moon shields the Earth from much of the radiation, allowing living things to thrive on Earth.The Moon shields the Earth from much of the radiation, allowing living things to thrive on Earth.
C The Earth’s oceans absorb a large percent of the radiation since 71% of Earth is covered in oceans, allowing living things to thrive on Earth.The Earth’s oceans absorb a large percent of the radiation since 71% of Earth is covered in oceans, allowing living things to thrive on Earth.
D The Earth’s atmosphere filters out much of the radiation, allowing living things to thrive on Earth.

Answer 1

D

The Earth's atmosphere — especially the ozone layer — absorbs and scatters much of the Sun’s harmful ultraviolet radiation, so very little of the most damaging UV reaches the surface. (The magnetic field also helps by deflecting charged solar particles, and organisms have evolved additional protections and repair mechanisms.)