Coal is a …………… solid stratified rock of organic and mineral matter.

1. combustible
2. non-combustible
3. renewable
4. None of the above.

…………… coal has …………… per cent of carbon content and is the most preferred variety of coal.

1. Lignite, 40
2. Peat, 50
3. Anthracite, 90
4. Bituminous, 80

Anthracite is ideal for domestic use as it is smokeless and has high …………… value.

1. industrial
2. calorific
3. volatile
4. demand

…………… is also known as brown coal and is lower grade coal.

1. Peat
2. Lignite
3. Anthracite
4. Bituminous