Final answer:
A pea plant heterozygous for seed color (Yy), seed shape (Rr), and pod shape (Ii) can produce 8 different gametes. To predict the offspring of a self-pollination, a 4x4 punnett square would need to be created.
Step-by-step explanation:
For a pea plant heterozygous for seed color (Yy), seed shape (Rr), and pod shape (Ii), there are several different gametes that could be formed. Each gene has two possible alleles, so for each gene there are 2^1 = 2 possible gametes. Therefore, the number of different gametes that can be made is 2^3 = 8. These gametes would be: YRI, YrI, yRI, yrI, YrI, Yri, yRi, and yri.
To predict the offspring of a self-pollination of this trihybrid, a punnett square would need to be created. Since there are 8 possible gametes, a 4x4 punnett square would be required. The columns and rows would represent the different gametes that could be produced, and the cells of the punnett square would show the potential offspring genotypes.