A small lesson.
A clearer next step.

A Punnett square shows possible allele combinations. Alleles are versions of a gene. This example uses a simple dominant and recessive inheritance model.

For these imaginary pea plants, capital T represents a tall allele. Small t represents a short allele. One capital T is enough for tall growth in this model.

Both parents have the combination capital T, small t. Put those two possibilities across the top and down the side of a four box grid.

Each box combines its column letter with its row letter. The results are two capitals, capital and small, capital and small, and two small letters.

Three boxes have a capital T. That predicts a three in four chance of tall growth. One box has two small letters: a one in four chance of short growth.

The allele combination is the genotype. The observable trait is the phenotype. Not every real trait follows this simple pattern.

These probabilities apply to each offspring. Four offspring do not guarantee exactly one short plant. Fill the boxes, count combinations, and state a chance.