How could a mutated gene produce a shorter protein than that produced by a normal gene?

Look at the following answer choices and determine which belongs in the both category. testable, can be disproven explains natural phenomena, has evidence to support it prediction, tentative, one or more scientists working together well established, many different scientists working independently, highly reliable

All individuals have two alleles for a given trait. according to mendel's these alleles are passed down one each from both mother and father.

Which phase of the cell cycle ensures that identical copies of the dna are made for daughter cells?