Plzzz help I’m being timed Question 4
During the process of transcription, which of the following events occurs directly after RNA polymerase recognizes the transcription start site of a gene?
A. A Free-floating nucleotide pairs up with the exposed DNA bases

B. A The DNA strand begins to unwind, separating the two strands.

C. A A complimentary RNA strand detaches itself from the DNA.

D. A The polymerase strings amino acids into a polypeptide.

Choose the incorrect statement (a) the motor end plate membrane is only capable of generating graded potentials, but it is contiguous with the skeletal muscle sarcolemma, which can generate action potentials. (b) propagation of an action potential through the t-tubules into the sarcoplasmic reticulum triggers the release of ca++ into the cytoplasm of a skeletal muscle fiber. (c) the generation of suprathreshold endplate potentials in multiple muscle fibers could be due to the increased frequency of action potential generation at the axon hillock of a single motor neuron. (d) a greater amount of ach would be found in the presynaptic vesicles of a motor unit that fired several action potentials after exposure to botulinum toxin, than in a motor unit that fired several action potentials after exposure to the venom of the krait snake (which contains α-bungarotoxin).