Cells make up the basic structure of an organism, and they perform basic life functions for the organism.
^the first one
Answer AND Explanation:
<u>FACTORS THAT CAUSE GENETIC VARIATIONS</u>
- Crossing over. At the chiasmata during prophase I of meiosis, breakage may occur and exchange of genetic information may take place. New gene combinations which result in variations.
- Independent assortment. The arrangement of homologous chromosomes at the equator of the spindle during metaphase of the first meiotic division is random. These homologous chromosomes segregate into different daughter cells which contain different genetic combinations which brings about variation
- Fertilisation permits parental genes to be brought together in different combinations. This is the cause of variations in members of the same family.
- Mutation is the spontaneous change in the genetic makeup of an organism. These changes may be inherited by the offspring therefore beginning variation.
<span>Homologous chromosomes have to attach together to the same spindle fiber during prophase 1. Then, some of them may go through crossing over, which switches fragments of them. Then, each pair of homologous will migrate to equatorial plane during metaphase 1. So, in the metaphase plate you will have pairs of homologous, both of them duplicated, but the 4 chromatides may be different due to crossing over (it depends on where the enzymes have cut and pasted in that process).</span>
Answer:
B
Explanation:
High and low tides are caused by the moon. The moon's gravitational pull generates something called the tidal force. The tidal force causes Earth—and its water—to bulge out on the side closest to the moon and the side farthest from the moon. These bulges of water are high tides.
