Concept:Ethene molecules act as small repeating units that join together to form a very large chain molecule called a polymer.
Explanation:The process is called addition polymerisation.
Ethene,
C2H4, is the starting unit or monomer.
When many ethene molecules react, their double bonds open up.
These molecules then link end to end to form a single long chain.
This long-chain product is known as polyethene or polythene.
Because many monomers combine into one giant molecule, the product is classified as a polymer.
Smaller combinations such as two units form a dimer, and three units form a trimer, but a long chain indicates a polymer.
Answer:C. polymer