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.
Answer:A radical (often, but unnecessarily called a free radical) is an atom or group of atoms that have one or more unpaired electrons. ... A prominent feature of radicals is that they have extremely high chemical reactivity, which explains not only their normal biological activities, but how they inflict damage on cells.
Explanation:CAN I GET BRAINLIEST PLZZZZZZZZZZZ
The leaves are smaller, meaning the plant cannot photosynthesize as fast as before. This means that the plant cannot produce as much energy and grows slower as a result.
Answer:Institutional Animal Care and Use Committees ( IACUC).
Explanation: it was formally introduced in 1986 with an amendment to the Animal Welfare Act and corresponding changes in U. S. public health service policy. It is the committee that investigates researcher to know if they are properly trained to perform animal procedures, as required by law.
