Answer:
number, variety and variability of organisms
Explanation:
The answer would be d. the population has increased and so has the demand for energy sources
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<span>, and exchange DNA. The nucleolus and nuclear envelope disappear.</span>