Kinesin-5 is a motor protein that binds to overlapping interpolar microtubules near the midzone of the mitotic spindle. each of these kinesin proteins has two motor domains that walk toward the plus ends of the microtubules to which the kinesin is bound. when is this kinesin active and how does it affect the spindle? choose one: o a. during anaphase a, kinesin-5 slides the microtubules past one another toward the spindle poles, pulling the poles together and shortening the spindle. o b. during anaphase b, kinesin-5 slides the microtubules over one another toward the spindle equator, pulling the poles together and shortening the spindle. o c. during anaphase b, kinesin-5 slides the microtubules past one another toward the spindle poles, pushing the poles apart and lengthening the spindle. d. during anaphase a, kinesin-5 slides the microtubules past one another toward the spindle poles, pushing the poles apart and lengthening the spindle. © e. during anaphase b. kinesin-5 slides the microtubules past one another toward the spindle poles, pulling the poles together and shortening the spindle.