By studying a particular species .
Cold air usually pushes warm air because cold air has a HIGHER DENSITY
It radiates light and heat, or solar energy, which makes it possible for life to exist on Earth. Plants need sunlight to grow. Animals, including humans, need plants for food and the oxygen they produce. Without heat from the sun, Earth would freeze.
The answer is C I don’t think this needs more explanation but if needed just ask!
Explanation:
An amino acid is an organic molecule that is made up of a basic amino group (−NH2), an acidic carboxyl group (−COOH), and an organic R group (or side chain) that is unique to each amino acid.
