The first two steps in the formation of the sun are listed below.

A cloud of gas and dust called nebula spins slowly.
The nebula collapses due to condensation of gases.
Which of these statements best describes the next step in the formation of the sun?
The cloud spins faster as it collapses and flattens into a disk.
The cloud slows down and expands to form a flattened disk.
The nuclear fission of the gas molecules takes place at the center of the disk.
The nuclear particles in the center of the nebula repel each other and move apart.

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).