The increase in the temperature
Crossing over at prophase I results in the linked genes (those on the same chromosome) becoming unlinked and separated. Prophase I is this first stage of meiosis, the chromosomes condense, form tetrads, and exchange DNA. The nucleolus and nuclear envelope disappear.
A because it has nice exponential curve
Answer:
So that they survive and can reproduce creating more of that species.
Some of the bacteria may be resistant to the antibiotic and survive