Amount of wear, and how long they are may contribute with age and maybe even coloration and pigment.
Carbon and nitrogen and an important element of living things. Nitrogen is a major component of DNA and amino acids while carbon can be found in almost all biomolecules. These elements, therefore, need to be renewed and recycled as they are utilized by ecosystems that is ever dynamic.
Adenine,guanine,cytosine,and uracil
<span>Cytotoxic t-cell subpopulations are specialized to combat intracellular pathogens, whereas helper t-cell subpopulations are specialized to combat extracellular pathogens.
</span>Cytotoxic t-cell are CD8+ cells. Cytotoxic t-cell uses granzymes to <span>kill </span><span>intracellular bacteria, that lives in the cytosol such as viruses. They identify the pathogen forgein peptids that are bounded to MHC-I on the cell surface.
</span>
cd4+ T helper (Th) cells include Th1, Th2, and Th17 cells. They contribute to aliergic reactions and fighting extracellular parasites.