Amino acid<span>, </span>any of a group of organic molecules that consist of a basic amino group (−NH2<span>), an acidic carboxyl group (−COOH), and an organic </span>R<span> group (or side chain) that is unique to each amino acid. </span>
Answer: Option B
Explanation:
The animals that live on the earth in many different regions because they are adapted to live in a particular habitat. The animals of the polar regions cannot adjust living the Sahara desert and the reptiles living in the desert cannot live in polar regions.
But many of the species are dependent on the seasonal change and they only emergence or produce during specific period of time.
But if due to global climatic change there will be no emergence of particular species and their species will be extinct over a period of time. So, the global temperature needs to be constant in order to support life of the species dependent on the seasonal temperature change.
Answer:
four billion years ago the earth had a layer of ozone gas
