C. natural selection.
This is because in smaller populations the more that two separate groups of animals don’t interbreeding the father they become until speciation occurs where they cannot interbreed between the two groups.
Answer:
peptide antigens by MHC class II molecules
Explanation:
Helper T cells are activated by peptide antigens by MHC class II molecules. These antigens express on the surface of antigen-presenting cells (APCs). After activation, the T helper cells divide and secrete cytokines to assist the immune response.
Without efficient nutrient absorption, our body won’t function properly leaving us susceptible to deficiencies and disease.
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