Question

part b - thinking critically
which three statements may correctly explain why the population size increases after time point c?
the few drug - resistant bacteria in the population reproduced, quickly leading to a large drug - resistant population.
between time points c and d, drug - resistant bacteria were reproducing faster than non - drug resistant bacteria were dying.
the population increase just after time point c indicates that antibiotic use was discontinued.
because the population grew more rapidly after time point c, the bacteria must have acquired a second drug - resistance mutation.
bacteria that acquired a mutation that conferred drug - resistance had a growth advantage over non - resistant bacteria.

Explanation:

1. Drug - resistant bacteria can reproduce and expand their population. If there are initially a few drug - resistant bacteria, they can quickly multiply to form a large drug - resistant population.
2. When drug - resistant bacteria reproduce faster than non - drug resistant bacteria die, the overall population size increases.
3. Bacteria with drug - resistance mutations have a growth advantage over non - resistant bacteria, allowing them to thrive and increase the population size. The statement about a second drug - resistance mutation is not necessarily true just based on the population increase, and the population increase does not directly imply antibiotic use was discontinued.

Answer:

The few drug - resistant bacteria in the population reproduced, quickly leading to a large drug - resistant population.
Between time points C and D, drug - resistant bacteria were reproducing faster than non - drug resistant bacteria were dying.
Bacteria that acquired a mutation that conferred drug - resistance had a growth advantage over non - resistant bacteria.