Earth's history. In the worst one, 250 million years ago, 96 percent of marine species and 70 percent of land species died off. It took millions of years to recover.
When it is said that mutation is the ultimate source of genetic variation it means that it creates several new combinations which is similar to meiosis and fertilization because <span> new alleles and genes appear. It is just about some common points.</span>
This is because toxins are ingested by organisms and accumulate in the fatty tissues. Theses toxins then become more concentrated in successive trophic levels of a food web biological magnification. Magnification occurs because the biomass at any given trophic level is produced from a much larger biomass ingested from the level below and therefore, top-level carnivores tend to be the organisms most severely affected by toxic compounds.
B-Kidneys
The kidneys act as filters that strain urea and excess salts from the bloodstream to release them in the urine.
