Bright sunlight, lack of competitors, and more carbon dioxide
The right answer is D (less responsive to antigens)
It is proven that, after puberty, thymus activity (an organ that is included in the lymphatic system, producing T cells that pick up antigens) decreases and that in adult and aged people the thymus has no role. Work done in humans indicate that in fact the cellularity begins to decline from birth in favor of lymphocyte perivascular spaces and connective and adipose tissue, which leads to a decrease in the capture of antigens.
Enzymes <em><u>act as catalysts in Chemical reaction of cells. </u></em>And they <u><em>can lower the required activiation energy for reaction in living organisms. </em></u>
A) Stone
They used materials they were available to them which was majorly limestone which is a type of stone.
