The reaction that joins thousands of small, identical molecules to form one very long molecule is called

(1) esterification (3) polymerization

(2) fermentation (4) substitution

The reaction that joins thousands of small, identical molecules to form one very long molecule is called:

(3) polymerization

Explanation:

In chemical compound chemistry, method|chemical change|chemical action} may be a process of reacting compound molecules along in an exceedingly reaction to make polymer chains or three-dimensional networks. There are several types of chemical process and totally different systems exist to classify them.

The question is asking to choose among the following reaction that joins thousands of small identical molecules to form one very long molecule and base on my further research, I would say that it would be (#3) polymerization. I hope you are satisfied with my answer and feel free to ask for more