Rebecca was deciding what color to paint her room. She was deciding between sky blue, sea green, or canary yellow. While thinking about which color would be best, she wondered why things had color at all, such as the sky being blue. What makes the sky appear to be blue? A. Only blue light can pass through the atmosphere without hitting particles. B. The particles in the atmosphere are naturally blue. C. Only blue light is absorbed by the particles in the atmosphere. D. Only blue light is reflected by the particles in the atmosphere.

To determine why the sky appears to be blue, let's analyze each option provided:

A. "Only blue light can pass through the atmosphere without hitting particles."

• This statement is incorrect. All colors of light can pass through the atmosphere, but they interact with particles in different ways.

B. "The particles in the atmosphere are naturally blue."

• This statement is also incorrect. The particles in the atmosphere, such as nitrogen and oxygen molecules, are not inherently blue.

C. "Only blue light is absorbed by the particles in the atmosphere."

• This statement is incorrect. If blue light were absorbed, the sky would not appear blue. Instead, it would appear in the color of the light that is not absorbed.

D. "Only blue light is reflected by the particles in the atmosphere."

• This statement is the closest to the correct explanation. The sky appears blue due to a phenomenon called Rayleigh scattering. When sunlight enters the Earth's atmosphere, it collides with gas molecules and small particles. Blue light is scattered in all directions more than other colors because it travels as shorter, smaller waves. This scattered blue light is what we see when we look up at the sky.

Therefore, the correct answer is: D. Only blue light is reflected by the particles in the atmosphere.