This phenomenon can be observed when several dominant genes are responsible for the manifestation of the same trait. If at least one dominant allele is present, then the sign will certainly appear. The types of gene interaction in this case may be different. One of them is accumulative polymers, when the degree of manifestation of a trait depends on the number of dominant alleles. This is the inheritance of the color of wheat grains.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.