Scientific explanations are the result of scientific reasoning. Whenever scientific reasoning is used, takes place.

The options are

A.) an active consideration of alternative explanations.

B.) a process to totally disprove alternative explanations.

C.) a process to prove a given explanation with logic.

D.) the collection of completely accurate observations.

The answer is D.) the collection of completely accurate observations.

Scientific reasoning results in a thoughtful process and consideration of several informations. This results in Scientific explanation as to the occurrence of such an event.

It is therefore imperative that whenever scientific reasoning is used there is the collection of completely accurate observations.

the unequal cytoplasmic division that  results  in  one egg  and three polar bodies ensures that a fertilized  egg has  ample nutrients  forits journey  to  the uterus.