Answer:
D
Explanation:
I may be wrong but I think it's D
A muscle fiber will respond to a stimulus when that stimulus reaches the threshold level. These local classified potentials which are mainly related with external stimuli extent the axon preliminary segment and construct up to they manage to extent the threshold value. The bigger the stimulus the larger the depolarization or try to reach threshold.
Answer: melanin
Explanation: Further, other cells contribute to the function of the epidermis. Melanocytes are cells that produce melanin, a compound involved in skin pigmentation produced in response to ultraviolet (UV) light exposure (6). Melanin can absorb energy from UV light to shield underlying tissues from damage.
<span>It
is important that antibodies have a symmetrical quaternary structure to create
two identical binding sites for antigens. An antibody is a relatively large
protein having a Y-shape. Plasma cells produce antibodies which are then used
by the immune system to fight off pathogens (e.g. bacteria and virus). The antibody
is able to recognize the antigen of the pathogen. It binds with it either to
neutralize it directly or “tag” the microbe for future attack by other parts of
the immune system. </span>