During meiosis, when does the ploidy (number of sets of chromosomes) get reduced from diploid (2n) to haploid (n)?

How are mutations continually being generated in a population (what are some of the causes of mutatuions? ) explain

1) what three conditions must be present for minerals to form through natural processes? 2) why are minerals considered inorganic substances? 3) how do oxides differ from other minerals that contain oxygen atoms? 4) how is a sulfide different from a sulfate? what makes native elements unique?

If animal agriculture was eliminated, how much grain would become available for human consumption?