what is the principle of dominance?

Answer 1

One of Gregor Mendel's great discoveries was the Principle of Dominance. He noted that when he hybridized two parents with different versions of a particular trait, one of those versions apparently disappeared in the hybrid (heterozygous) offspring. If he then mated those offspring to each other, the vanished trait reappeared in the third generation, apparently completely unchanged despite being invisible in generation 2. He named the version of the trait which was visible in the hybrids the dominant and the one that was invisible in the hybrids the recessive.