Cuticles antennae auditory ossicles are parts of arthropods bodies that allow them to breathe air
The two DNA<span> strands are known as polynucleotides since they are </span>composed<span> of simpler units called nucleotides. Each nucleotide is </span>composed<span> of a nitrogen-containing nucleobase—either cytosine (C), guanine (G), adenine (A), or thymine (T)—as well as a sugar called deoxyribose and a phosphate group.</span>