Question

Polyester is made up of the repeating unit of a chemical called:
$\left( A \right)$ Ester
$\left( B \right)$ Ether
$\left( C \right)$ Cotton
$\left( D \right)$ Ethene

Answer 1

Polyester is a polymer, A polymer is a substance or compound that consists of very large molecules or macromolecules which are composed of many repeating units (also called monomers).
For example, polyethene, nylon, polyamide and Bakelite.

Complete answer:
In the given question we have given the polymer is polyester which is made up of a monomer (repeating unit) known as ester. Polyester is made by a reaction involving an acid with two carboxylic functional groups and with two alcohol groups. They combine and condense water to polyester for several times.
Esters are liquid colorless, pleasant smell, while those of higher acids are colorless solids. The boiling points of methyl and ethyl ester are lower than those of the parent acid due to absence of hydrogen bolding. Ester consists less of carbon almost soluble in water whereas ester contains large numbers of carbons insoluble in water.

The correct option is $A.$

Additional information:
Polyester is a man-made synthetic fibres, the material is used extensively in clothing. It is a strong fibres and consequently can withstand strong and repetitive movement. They are also hydrophobic.
Uses of polyester: Generally it is used in outerwear because of its high tenacity and durability. It is also used to make garments and jackets because of its hydrophobic property. Polyester is often used in pants and shirt either by itself or as a blend because of its wrinkle-resistant property.

Note:
For polymerization of monomers combines in the influence of temperature, pressure, and a catalyst to create a polymer. A polymerization process requires that monomers should have the capacity to combine.