Explain the law of dominance using a monohybrid cross.

Characters coded by discrete units called factors
E.g., Character - Height [alleles] - T/t.
 Factors occurs in pairs, which can be similar or dissimilar. Pairs.
Similar Pair - TT/tt, Dissimilar pair - Tt.
* In a pair dissimilar of factors (Tt ) one factor of pair dominates (T) the other factor (t).
Monohybrid cross :
* Cross pollination between true breeding tall and dwarf plant, result all tall plants in F₁ generation.
* Self pollination in F₁ plants result in F₂ progeny.
* The F₂ progeny show 3: 1 ratio of dominant trait and recessive trait.
TT × tt (parents)
Tt $\to$F₁ generation
Self pollination of F₁ progeny
Tt × Tt