Question

select all that apply
which of the following explain the natural selection of antibiotic resistance in bacteria?
when an antibiotic is introduced, the bacteria create a new gene that confers resistance on the population.
a small number of individuals in a population have mutations in existing genes that provide resistance against a given antibiotic.
the presence of an antibiotic selects for the creation of new genes.
the presence of the antibiotic selects for individuals with antibiotic resistance.

Explanation:

• In natural selection, mutations (changes in genes) already exist in a population. Bacteria do not create new genes in response to an antibiotic. So, the statement "When an antibiotic is introduced, the bacteria create a new gene that confers resistance on the population" is incorrect.
• A small number of bacteria in a population may have mutations in existing genes that provide resistance against a given antibiotic. This is a key part of the natural - selection process for antibiotic resistance.
• The presence of an antibiotic does not "select for the creation of new genes". Mutations are random and pre - exist in the population.
• The presence of the antibiotic selects for individuals (bacteria) with antibiotic resistance. Bacteria with resistance are more likely to survive and reproduce when the antibiotic is present.

Answer:

B. A small number of individuals in a population have mutations in existing genes that provide resistance against a given antibiotic.
D. The presence of the antibiotic selects for individuals with antibiotic resistance.