Final answer:
The monomer from which polyethylene is made has hydrogens (H) attached to the C=C.
Step-by-step explanation:
The monomer from which polyethylene is made has hydrogens (H) attached to the C=C. When polymerized, the monomer ethylene (CH₂=CH₂) is transformed into a solid material made up of long chains of -CH₂- units called polyethylene. The relative lengths of the chains and any branches control the properties of polyethylene, such as its density and flexibility.