Humans have

an exoskeleton

jointed appendages

segmentation

no coelom

Humans have an exoskeleton.

Explanation:

Exoskeletons contain rigid and resistant components that fulfill a set of functional roles in many mammals and humans including protection, excretion, sensing, support, feeding and acting as a barrier against desiccation in terrestrial organisms.

the nitrogen cycle provides nitrogen to the ecosystem from the atmosphere, ground and oceans. nitrogen is an important component of complex molecules such as amino acids and nucleotides, which lead to the creation of proteins and dna, the building blocks of all life. plants absorb nitrogen in the form of ammonium, nitrate ion and, on rare occasions, as amino acids. animals receive nitrogen necessary for biological processes from feeding on living or dead organic matter.