Final answer:
Auxotrophs are conditional lethal mutants that can be identified using replica plating. This technique involves comparing growth on a complete plate with growth on a nutrient-deficient plate. Auxotrophs can grow on the complete plate but not on the nutrient-deficient plate.
Step-by-step explanation:
Conditional lethal mutants, specifically auxotrophs, are identified using a technique called replica plating. This technique involves comparing growth on a nutritionally complete plate with growth on a medium lacking a specific nutrient, such as histidine. Auxotrophs are mutant cells that can grow on the complete plate but not on the nutrient-deficient plate. Replica plating allows researchers to identify these auxotrophic mutants and study them further. The identification of auxotrophic mutants is important in various fields, including genetics and microbiology.