Which category of materials does concrete belong to and why? a. it’s a synthetic polymer because it’s a product of a chemical reaction. b. it’s an alloy because it contains layers of different components. c. it’s a ceramic because it contains substances such as sand and clay. d. it’s a composite because it’s a mixture of cement, sand, and other granular pieces.

Option D, It’s a composite because it’s a mixture of cement, sand, and other granular pieces.

Explanation:

Composite is a mixture which is prepared by blending different substances possessing different physical and chemical properties.  

In case of concrete, the ingredients are -

a) Cement  

b) sand

c) aggregate (granules)  

d) Wire mesh, iron rods or any other substance that has high tensile force.

Here,  the cement acts as a matrix and the gravels and aggregate act as reinforcement. Concrete at the stage of placement is further reinforced by wire mesh or iron rod. Since concrete is good in compressive strength but weak in tensile strength, iron rods provide tensile strength to concrete mix.

Thus, concrete being a mixture of different substances is considered a composite mixture

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predators: eagles, frogs, wolves, owls