-sneezing -sexual contact can transfer pathogens from one person to another,-if you have a cut or a break in your skin, microbes can gain direct access to your bloodstream,-by consuming contaminated food and drink.-if the pathogen goes airborne
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.
Aesthetic potentially due to the decay but also environmental
The given question is incomplete as options are not provided, however the options are as follows:
A. a large surface area-to-volume ratio
B. ability to form stacks known as rouleaux
C. a convex shape allowing for more efficient transport of oxygen
D. ability to bend and flex when entering capillaries
Answer:
The correct answer is - option C.
Explanation:
RBC cells are biconcave in the shape it is form shape of dub bell in general. These cells are small, round. The biconcave shape of the blood cells helps in the flow of the blood easily and these cells have no nucleus like other cells to have high amount of hemoglobin that is a pigment that carry oxygen and other gases for easy gaseous exchange.
Due to their flexible biconcave shape they can bend and flex accordingly during entering capillaries. The shape of the RBC helps in making stacks and large surface to area ratio.
Thus, the correct answer is - option C.
