Nitrogen, oxygen and argon are the three most abundant elements in the atmosphere, but there are other key components that are required for supporting life as we know it on earth. One of those is carbon dioxide gas.
Answer:
The answer is A
Explanation:
The gene sequence inscribed in DNA, and in RNA, is composed of tri-nucleotide units called codons, each coding for a single amino acid. Each nucleotide sub-unit consists of a phosphate, deoxyribose sugar and one of the 4 nitrogenous nucleotide bases grouped into 2 categories, purine and pyrimidine.
Answer:
The cornea
Explanation:
The cornea is the only part of a human body that has no blood supply; it gets oxygen directly through the air.