Limestone and graphite
Limestone and clay
Chalk and graphite
Clay and graphite
Answer is Right!
Answer is Wrong!
The correct answer is A. Limestone and clay.
Cement is a binding agent that is used to hold together other materials, such as sand and gravel, to form concrete. It is made by strongly heating a mixture of limestone and clay. The heat causes the limestone to decompose into calcium oxide and carbon dioxide, and the clay to decompose into silica, alumina, and iron oxide. These materials then react with each other to form cement clinker, which is ground into a powder and mixed with water to form cement.
Chalk is a type of limestone that is composed of calcium carbonate. Graphite is a form of carbon that is soft and black. Neither chalk nor graphite are used to make cement.