1.
Coal is an example of:

2.
Rocks which are formed by the solidification of lava, are:

3.
The lightest layer of the earth is:

4.
The core of the earth is also known as:

5.
Which of the following rocks is metamorphic equivalent of sandstone?

6.
What is anthracite?

7.
Which of the following layers of the earth is believed to have the heaviest mineral materials of highest density?