Brown-eye genes are dominant over blue-eye genes. what is the best explanation for the fact that all the blue-eye alleles have not disappeared in the human population?

Dominant genes will come before recessive. Someone with brown-eye and blue-eye genes will have brown eye since it's the dominant one. So sometimes blue -eye allele is hidden because it's not express, but not always.

People with blue eyes must have all blue-eye allele. Therefore, if there are people with blue eyes you can conclude that blue-eye allele has not disappeared in the human population.

If there is no factor that intervenes with population breeding, Hardy-Weinberg equilibrium will be maintained and that can be used to explain why the all the blue-eye alleles have not disappeared in the human population

Aneutral atom must have the same number of neutrons and protons? no, they must have the same number of protons and electrons