Human beings accumulate before excreting nitrogenous waste.
nitrogen
ammonia
urea
uric acid

urea

Explanation:

Excreta is the biological name used for nitrogenous residues produced by metabolism and should be eliminated in order to allow a state of internal equilibrium (homeostasis) of the organism, being the types of excreta in different groups of animals. These groups are divided between animals that accumulate ammonia, urea or uric acid prior to the release of nitrogen residues.

The human being is a ureotelic animal, that is, an animal that accumulates urea before excreting nitrogen waste.

Urea is a water-soluble substance, but less toxic than ammonia. Synthesized in the vertebrate liver from the reaction of ammonia and carbon dioxide, it represents an adaptive strategy of certain land animals: annelids, cartilage fish, amphibians, and mammals.

an active site is a region that is present on an enzyme where the reactants or the substrate molecules we can say bind and experience a chemical reaction. the substrate is basically a reactant whose concentration is changing and that is converting into a product after binding at the active site of an enzyme

it also supports my hypothesis. if you rest first you can squeeze the clothespin more times. from the data i collected the average of the eight people concluded exercise makes your muscles more fatigued and less able to squeeze the clothespin compared to resting before squeezing.