Concept:Natural rubber is a polymer made by the addition polymerization of isoprene units.
Explanation:Natural rubber is obtained from the latex of rubber trees.
It is a linear polymer of
isoprene (2-methyl-1,3-butadiene).
The chemical formula of isoprene is
CH2​=C(CH3​)−CH=CH2​.
In natural rubber, isoprene units link together in a cis-1,4 configuration.
Thus, the monomer that repeats to form natural rubber is isoprene.
Answer:Option A. Isoprene
