C, Proteins is the correct answer
Answer: A
Explanation:
Our universe was born from the Big Bang about 13.5 billion years ago. ... Our solar system began forming about 4.6 billion years ago within a concentration of interstellar dust and hydrogen gas called a molecular cloud. The cloud contracted under its own gravity and our proto-Sun formed in the hot dense center.
Answer:
Plants and animals use oxygen to respire and return it to the air and water as carbon dioxide (CO2). CO2 is then taken up by algae and terrestrial green plants and converted into carbohydrates during the process of photosynthesis, oxygen being a by-product.
Explanation:
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