Rats account for a decent amount of biomass globally. They are intermediate predators, eating a lot but also being eaten. If they went extinct, they would stop eating many insects and seeds / fruits -- the former would gain significantly in population, and the latter would lose some of their pollination. Both factors would harm the viability of at least some species of plants, by adding to plant eaters (insects) and reducing plant reproduction. Rats' predators would also suffer if they went extinct. The primary predators are birds of prey, such as hawks and owls. However, other animals such as skunks, foxes, weasels, coyotes, and even wolves eat rats. For predators in marginal environments, the loss of such a food source could drive them out of a habitat area.
burns are estimated by class, 1st degree, 2nd degree, etc. there are characteristics associated with each degree. if you can see the muscle and fat tissue, that would be a 4th degree burn...
DNA replication is called semiconservative because the two resulting DNA molecules each have one new DNA strand and one old strand from the original DNA molecule.
That then right after heat it evaporates and then the water that is still in the bowl lowers because of the heat that sends out water molecules that just disappear. :)