<span>In biochemical reactions,
it is mostly triggered by enzymes. Enzymes are important components in the
process that involves metabolism and digestive functions, further, most of
these enzymes are proteins. Proteins are biological macromolecule and mostly
composed of enzymes. Proteins play a role in the physical make-up of a cell or
acts as a cytoskeleton –maintains cell shape and figure. These proteins plays
different roles and works with nucleic acids and other macromolecules in the
cells including cell cycle, cell adhesion, immune response and cell indicators.
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Answer:
The respiratory system brings oxygen unto the lungs, while the circulatory system delivers oxygen throughout the body.
Explanation:
if I remember correctly I'm pretty sure all cells have a nucleus
