Its so simple. Two alleles means three genotypes.
consider a gene has two alleles A(blue eyes) and a(brown eyes)
possible combinations:
1. AA - Homozygous dominant -Blue eyes.
2. Aa - Heterozygous - Blue eyes.
3. aa - Homozygous recessive - Brown eyes.
Molten Lava, and not solid like the crust.
The amount of atomic mass between them
The condition that distinguishes animals and plants from inorganic matter, including the capacity for growth, reproduction, functional activity, and continual change preceding death.
This is the definition of life.
