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.
Answer:
An acid increases the hydrogen ion concentration in a solution, while a base decreases the hydrogen ion concentration. pH is used to measure the concentration of H+ ions ([H+]) and therefore, whether a substance is acidic or basic (alkaline).
Explanation:
Please make mine the brainliest
Basically the seed contains 2 parts, the testa, which is the seed coat that protects the seed and cotelydon, which is the inside of the seed, containing the radical and plumle.
for seed to germinate, we need 3 basic conditions,
warmth, it is the suitable temperature for seed germination, it can influence the activity of enzymes. providing a optimum temperature
water, to soften down the testa so that the shoot can break out from the testa
and oxygen, for aerobic respiration
.
If these conditions are absent, the seed may be in the state of dormancy. where is won't germinate until it meets the suitable conduction.
after that, the enzyme will digest the nutrient inside the seed and provide amino acid, which is necessary to seed germination. and meanwhile the aerobic respiration provides energy, so that the plumlecan shoot out, and be the shoot of the plant.
and then until it grows leaves, it'll start to complete photosynthesis, instead of using the nutrients inside the cotelydon.
<span>Chroloplasts Acts as a main role in photosynthesis.Chloroplasts likely orginated from engulfed "prokaryotes" that once lived as independent organisms. They are also considered to be originated from "cyanobacteria" through endosymbiosis—when a eukaryotic cell engulfed a photosynthesizing cyanobacterium that became a permanent resident in the cell.</span>
Sorry I don’t understanddddd:/
