Explanation:
Meiosis makes genetic variety possible. It makes sperm & egg cells called gametes. Each gamete has 23 chromosomes. To make a diploid cell two gametes (sperm & cell) come together.
During prophase 1 the chromosomes pair up with their homologous pairs so they can transfer their genetic information and exchange it between each other. It makes recombinant chromosomes that influence the genetic diversity between the same people.
Now they are in metaphase 1, the chromosomes are in pairs in the middle of the cell. In anaphase 1, the chromosomes are pulled away by the spindle fibers. Then in telophase 1, there are two formed nuclei. Cytokinesis 1 then splits the cytoplasm.
Now they are in meiosis 2. During prophase 2, there are chromosomes and the spindles are starting to form again without crossing over like in prophase 1. In metaphase 2, chromosomes are going to line up in the middle in both cells unlike during metaphase 1 where the chromosomes were only in pairs. In anaphase 2, only the chromatids are being pulled away by the spindle fibers. Next in telophase 2 the nuclei reform and the 2 cells are each going to divide into 4 cells. Finally, cytokinesis completely splits the cytoplasm.
Keeping in mind that each sex only produces one type of gamete cell (sperm or eggs), and of the independent assortment and crossing over of chromosomes, the end result will be diversity.
The first step of cellular respiration takes place in cytoplasm of the cell called glycolysis. Cellular respiration is an aerobic process that requires oxygen and gives off carbon dioxide and it usually involves the complete breakdown of a glucose molecule with the use of oxygen molecule and then produces a net gain of 2 ATP's.
I think the the ribs are not a solid sheet because they need to be able to expand so the lungs can get an adequate amount of air in the lungs. The brain just needs to be protected and doesn’t need to expand so it’s a solid sheet. The skull seems to be the better protector at first because the ribs can break and puncture a lung, harming your breathing but if you do hit your head your brain can start swelling and the skull doesn’t allow any room for expansion. Head injuries are much more dangerous, especially if the brain starts swelling. Rib injuries seem much simpler to fix and less dangerous.
Answer:
The tropical regions are subjected to extreme changes of season. The polar regions were populated earliest in the history of Earth.
