Genetic probabilities

3.21b Predict the probabilities of outcomes from mono hybrid crosses

F1 cross.

Between an F1 offspring crossed with an F1 offspring.

The parent phenotype is a red petal crossed with a red petal and the parent genotype is Rr x Rr the heterozygotes.

meiosis: The alleles need to be separated one into each type of gamete.
Half of the pollen grains would be R and the other half would be r.

Genotype offspring: RR : 2Rr : rr

These are probabilitties or chances not numbers.

Phenotype ratio (F2)   Red : Red : White

       3:1 ratio    75% red and 25% white.

These are just chances.