What role does calcium play in muscle contraction?

It is the third week of the semester. dolly has registered for five courses because she is in a hurry to finish fire protection technology aas program. dolly is in aca 122, pol 120, eng 111, developmental math, and cis 110. she has realized that she cannot be successful in all of the classes at the same time because she also works 30 hours per week and has two small children. she wants to withdraw from one or more of her classes, but she doesn’t know which ones to drop. what college policies and procedures does dolly need to understand to her make this decision? what advice would you give her?