Answer:
The magma cools very slowly. As magma cools minerals are formed into an interlocking arrangement producing an igneous rock. As magma cools it undergoes reactions that form minerals. The rate of cooling is very important.
Explanation:
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Answer:
The presence of ozone enabled organisms to develop and live on the land. Ozone played a significant role in the evolution of life on Earth, and allows life as we presently know it to exist. These atoms combined with remaining oxygen (O2) to form ozone (O3) molecules, which are very effective at absorbing UV rays which could be injurious to organism existence
Explanation:
There are four haploid cells after meiosis and cytokinesis. There are two diploid cells after mitosis and cytokinesis. It's easy to get confused. :D
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.
