Answer:
in aerobic respiration oxygen is needed and it occurs in mitochondria.
One way of creating a variation in a population is through genetic replication errors. This will make new type of alleles. Environmental factors causes variation such as affecting enzyme activity and function. The changes would show in the phenotype of an organism.
Gymnosperms have pollen but no flowers.
It's A I believe. None of the answers seem to make sense.
