Question

the descendants of a single, pure microbial culture are defined as a ______.

class
family
strain
species

Explanation:

A strain is defined as a group of microbial descendants originating from a single, pure microbial culture. Class, family, and species are broader taxonomic ranks that group organisms based on shared genetic and phenotypic traits across multiple cultures, not from a single pure culture lineage.

Answer:

O strain