Answer:
Since a species' chromosome count doesn't change from generation to generation, meiosis requires that the number of chromosomes in germ cells be cut in half. Meiosis, unlike mitosis, achieves this accomplishment by requiring a single round of DNA replication followed by two rounds of cell division.
Humans ferment lactic acid in muscles where oxygen becomes depleted, which is why sometimes if you finish a run and don't stretch soon you have have discomfort. <span />
Http://www.biocab.org/Carbon_Dioxide_CO2.html
