Answer:
B.The sperm and egg.
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Answer:
Generation of an action potential in the neuron.
Stimulation of Ca2+ entry into the neuron
Release of acetylcholine into the synapse
Depolarization of the muscle fiber membrane
Explanation:
The following events takes place in the vertebrate neuromuscular junction
a) Nerve Action Potential - Action potential reaches the axon terminal
b) Entry of calcium ion - The calcium ion reaches the axon terminal and enter into the presynaptic terminus after which the Synaptic vesicles fuse with the membrane of axon terminal
c) Releasing of Arch Quanta - Acetylcholine is released into synaptic cleft which then binds to the receptor sites on motor end plate
d) The Na+/K+ channels opens and Motor end plate becomes depolarized.
Answer:
Helper T cells are arguably the most important cells in adaptive immunity, as they are required for almost all adaptive immune responses. They not only help activate B cells to secrete antibodies and macrophages to destroy ingested microbes, but they also help activate cytotoxic T cells to kill infected target cells.
Explanation:
Helper T cells become activated when they are presented with peptide antigens by MHC class II molecules, which are expressed on the surface of antigen-presenting cells (APCs). Once activated, they divide rapidly and secrete cytokines that regulate or assist the immune response.
Answer:
may be they are history and geography
Answer:
Ribosomes.
Explanation:
The function of ribosomes is to make protiens by joining amino acids together.