Percentage of human sperm cells carry an X chromosome is C 50%
<span>The correct answers are that it lacks cells, DNA, and cannot maintain homeostasis. It doesn't have any organic matter and homeostasis is impossible because it would turn off eventually. It doens't have DNA and it doesn't reproduce. It's just plasma and it is not a living being, it just moves because of the chemical reactions that occur. </span>
Dependent reaction is the factor that is observed and measured
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.