[Solved] During the contraction of a vertebrate skeletal muscle fiber,calcium ions A)break cross-bridges by acting as a cofactor in the hydrolysis of ATP. B)bind with troponin,changing its shape so that the myosin-binding sites on actin are exposed. C)transmit action potentials from the motor neuron to the muscle fiber. D)spread action potentials through the T tubules. Abused Animals: Animals that suffer harm or cruelty at the hands of humans, often sparking concern for animal rights and welfare. Financial Contribution: A monetary gift, donation, or investment made to support a cause, project, or organization. Ad Hominem: The fallacy of using a negative trait of a speaker as evidence that the speaker’s statement is false or the argument weak. Strip Club: An adult entertainment venue where strippers provide erotic dances and performances.