minomawari-e

1.

What is the radioactive material emitted as a gas from sources like granite and concrete?

Radon

Oxygen

Carbon dioxide

2.

What does the ionizing radiation near the ground surface come from?

Forest

Sea water

Granite

3.

Among the three major nutrients required for plant growth, which contains radioactive material?

Nitrogen

Phosphorus

Potassium

4.

How long has ionizing radiation existed on Earth?

460 thousand years ago

4.6 billion years ago

46 trillion years ago

5.

What is the ionizing radiation traveling around the universe called?

Cosmic ray

Radioactivity

Radioactive material

6.

When was the universe born?

138 years ago

1.38 million years ago

13.8 billion years ago