Find the TRUE sentence. Select one:a. In covalent bonds, pairs of valence electrons are shared between two atoms. b.In non-polar bonds, pairs of valence electrons are attracted towards the most electronegative atom. c.In non-polar bonds, pairs of valence electrons are attracted towards the most electropositive atom. d.In polar bonds, pairs of valence electron pairs are shared equally between two atoms.

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).