One, a lot of mass extinctions are based on theories by scientist. Two, they all caused major changes in the Earth's systems (Ex. ecology, atmosphere, surface, and waters). Three, they all have theories on what caused it.
Also this is obvious but in all mass extinctions they wiped out a lot of lifeforms, 90% of anything that has EVER lived on the Earth is extinct.
Hope this helps! :-)
Energy from the Sun fuels life on Earth.
Sunlight allows plants, algae and cyanobacteria to use photosynthesis to convert carbon dioxide and water into organic compounds like carbohydrates. This process is the fundamental source of organic material in the biosphere.
"A gene pool consists of all genes, including all the different alleles that are present in a population. Number of times an allele occurs in a gene pool compared with the number of times other alleles occur. In genetic terms, evolution is any change in the relative frequency of alleles in a population."
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2. Stimulating antibody production.
Explanation:
