Because it’s good for the environment to have a good balance and not to much of one thing
The two strands of a DNA molecule have complementary base pairs, the nucleotide sequence of each strand automatically supplies the information needed to produce its partner.
Tigers are a very important part of the food chain, but sadly they are going extinct. Their habitats are being destroyed, forcing the tigers to kill farmers livestock. In some countries tigers are still used for medicinal purposes, so they are often hunted for their teeth and pelts. Tigers may not seem important but they play a very important part on the food chain. Without these tigers the population of boars and other prey would sky-rocket and that would not be good for the environment.
Some scientists hypothesize that the eukaryotic cells are really the result of symbiotic processes!
Specifically, the internal organs of the cells could be a remnant of a symbiotic relationship in which one cell lived inside of another cell. These two cells then both split upon reproduction and eventually the cell inside was reduced to an organelle.
But according to this theory, it is very likely that the prokaryotic cells engaged in a number of symbiotic relationship, and that this actually lead to the emergence of eukaryotic cells!
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Answer:
The weather change as the earth warms because since,20th century due to human activities, particularly fossil-fuel burning which increases heat- trapping greenhouse gas levels in Earth's atmosphere.