How do you describe that cells are the basic units of structure to a 7 year old?

Dominance the dominant allele doesn’t fully mask or hide the recessive. for example, a red carnation with a white carnation will produce a carnation. one gene one trait. well most of the time than one gene controls a trait. we are all different but genetically speaking we are % similar with regards to genetic makeup.

Imagine that a mouse has white fur because of a mutation in its dna. which of the following conclusions can be drawn

What is the key to the recognition of codominance?