Afossils
Bcrystals
Cminerals
DIgneous rocks
Answer:
A. fossils
Read Explanation:
Rocks
The diversity of rocks (different colours and hardness) is due to its constituents. The constituents of rocks are called minerals.
Based on the mode of formation, rocks can be classified into 3 - igneous, sedimentary, and metamorphic.
Igneous rocks
Formed by the molten rock material rising through the fissures in the crust and solidifying. Eg:- granite, basalt.
As all other rock types are formed from the igneous rocks, they are called primary rocks.
Sedimentary rocks
Rocks undergo weathering. The debris so formed will be deposited in the low regions as layers and gradually get lithified and transformed into sedimentary rocks. Eg:- sandstone, limestone.
As the sedimentary rocks are formed in layers, they are also known as stratified rocks.
The remains of ancient plants and animals found in sedimentary rocks are called fossils. Coal, petroleum, natural gas, etc. Are called fossil fuels.
Metamorphic rocks
Formed when rocks undergo physical and chemical changes due to high temperature and pressure. Eg:- marble, slate.
Metamorphic rocks are prominent in Kerala.