#Question id: 5678

Following process and their mechanism during fertilization in mammals.

a. Rheotaxis	i.A sensing mechanism in which, the oocyte and its accompanying cumulus cells secrete molecules that attract capacitated sperm toward the egg during the last stages of sperm migration
b.  Chemotaxis	ii.It is a transient event, and sperm are given a relatively brief window of competence during which they can successfully fertilize the egg.
c.  Capacitation		iii.it is the ability to sense temperature difference and preferentially swim from cooler to warmer sites is found only in capacitated sperm.
d. Thermotaxis		iv.Sperm receive long-distance directional cues from the flow of liquid from the oviduct to the uterus and they will migrate against the direction of the flow—using CatSper calcium channels to sense calcium influx and monitor the direction of the current

Which of the following option is correct?