Answer:
The ozone layer helps reduce the amount of UV rays that enter the atmosphere
Explanation:
Hope this helps you out
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.
When looking at a Neuromuscular Junction (NMJ), we know that neurotransmitters (NT) are released from the presynaptic cell and they then bind to the receptors that are located on the postsynaptic cell - this causes the effect of the NT being released.
So we are told that NT are still being released, however they are not having an effect. This would mean that they are probably being blocked by something - in this case, it seems that the neurotoxin is the culprit in the blocking of these receptors.
Therefore, if the NT cannot bind to the receptors on the postsynaptic cell, they are not going to have any effect, no matter how much NT is being released.
So the answer in this case is: The neurotoxin is most likely C) Blocking the receptors on the postsynaptic cell.
