Cell theory states: all living things are composed of one or more cells; a cell is the smallest unit that still retains the properties of life; and new cells only come from cells that already exist. based on cell theory, why is a virus considered non-living? a) a virus does not have a nucleus. b) a virus does not contain genetic material. c) a virus is too small to be considered a cell. d) a virus cannot reproduce itself without a host cell.

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).