Which process involves the fusion of male and female gametes resulting in the formation of a zygote?

A substitution mutation is a type of point mutation where one base in the DNA sequence is replaced by another base.

Choice A is incorrect because a deletion mutation occurs when one or more bases are removed from the DNA sequence.

Choice B is incorrect because an insertion mutation occurs when one or more bases are added to the DNA sequence.

Choice D is incorrect because an inversion mutation occurs when a segment of DNA is reversed within the chromosome.

In a well-designed experiment, all variables apart from the treatment should be kept constant between the control group and treatment group.

This means researchers can correctly measure the entire effect of the treatment without interference from confounding variables.

Choice B) Independent variable and dependent variable is incorrect because these are not groups but rather variables.

The independent variable is manipulated by the experimenters while the dependent variable is measured to see if it changes as a result of the manipulation.

Choice C) Experimental group and non-experimental group is incorrect because a non-experimental group is not a term used in experimental design.

The correct term for the group that does not receive the treatment is control group.

Choice D) High level and low level of the independent variable is incorrect because these are levels of the independent variable, not groups.

In an experiment, there can be multiple levels of the independent variable, but they are applied to different groups (e.g. control group, treatment group).