Explain a trend or pattern you observe in the graph

Gametes with single dominant and recessive alleles in equal proportion i.e. half of the gametes will have dominant allele while the other half will have the recessive allele.

Explanation:

Gregor Mendel crossed purebreeding pea plants. He crossed a purebred dominant pea with tall traits (TT) and a purebred recessive pea with short traits (tt).

In 1860's, Mendel discovered the principles governing heredity. One of his principles is the law of segregation, which states that allele pairs separate during the formation of gamete. Relating to this law, Mendel discovered that

1. A gene exists in more than one form (2) called alleles, inherited from each parent. One allele is capable of masking the expression of another. The allele that masks or is expressed is called DOMINANT allele while the allele being masked is called the RECESSIVE allele.

2. When gametes are produced (by meiosis), allele pairs separate, leaving each cell with a single allele for each trait.

In a heterozygous state i.e. when two alleles of a pair are different, which is the typical genotype of Mendel's F1 generation, one type of the gamete will contain a dominant allele while the other type will contain a recessive allele.

Heterozygotic organism undergoes meiosis to produce gametes with an equal frequency of the allele i.e half (1/2) of the gametes will possess the dominant allele while the other half will possess the recessive allele.