They survive without water by entering a special mode, otherwise called as shriveling. They can lose even 95% of water in their body and still live, even though they would look like dead plants, they would actually be alive. In the absence of water, tardigrades use a sugar called trehalose, which becomes their source of life until they find some water.
Meiosis produces cells (germ cells or gametes) with only half the DNA, or chromosomes, as normal cells (somatic cells). This is called haploid or referred to as "n" number of chromosomes. Normal body cells have doubke that, called "2n," or diploid. For humans our n = 23, so germ cells (haploid) have only 23 chromosomes, while somatic (normal body) cells have "2n" or 46 chromosomes. It is important to only carry half the number of chromosomes or DNA (n), because it is going to combine with another half (n) when sperm meets egg during fertilization. This n + n = 2n restores the diploid number of chromosomes (DNA) in a zygote, the first cell of a future embryo, fetus, and new human being.
Explanation:
The valence electrons determine the group the elements belong in the periodic table. For example, the element sodium, Na, has a valence electron of one and so it belongs to Group 1 in the periodic table. Another example is Aluminium, Al, which has a valence electron of three and therefore it belongs to Group 3 in the periodic table.
