Answers and Explanations

Earth and Space Science Practice Questions

1. B

   The ozone layer is found in the upper stratosphere.

2. C

   The mantle lies beneath the Earth's crust.

3. A

   Cirrus clouds are found at the highest altitude of all clouds.

4. B

   Life on Earth has existed for approximately 3.5 billion years.

5. B

   The oceanic tides are caused by the gravitational pull of the Moon on the Earth.

6. C

   Nitrogen accounts for about 78 percent of the composition of the atmosphere.