Answer:
D Butterfly, coral and amoeba came from pre existing cells
Explanation:
It is definitely not a primary source: this would be a book itself.
Now, is it a tertiary source? I don't think so: the author of the review should have read the book and should only be referring to this book in the review.
I think it's a secondary source.
I think that the answer is 40...................................
Triggering of the muscle action potential occurs after Ach binds to chemically gated channels in the motor end plate membrane. Acetylcholine (Ach) is a neurotransmitter produced by nerve cells.
An action potential is an electrical signal that travels along the cell membrane as a wave.
This action potential (muscle action potential) drives the contraction of muscle fibers.
When the action potential reaches the neuromuscular junction (i.e., the motor end-plate), acetylcholine (Ach) is released into the synaptic cleft.
Subsequently, Ach can bind and open specific channels localized on the surface of the muscle cells, thereby depolarizing them and triggering muscle contraction.
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