1. **Problem:** Predict the phenotype of offspring from a test cross between a seedless orange (ss) and an orange with seeds (Ss). 2. **Formula and rules:** In genetics, a test cross involves crossing an individual with a dominant phenotype but unknown genotype (here Ss) with a homozygous recessive individual (ss) to determine the genotype of the dominant individual. 3. **Step-by-step solution:** - The seedless orange genotype is $ss$ (homozygous recessive). - The orange with seeds genotype is $Ss$ (heterozygous). - The possible gametes from $Ss$ are $S$ and $s$. - The possible gametes from $ss$ are only $s$. 4. **Punnett square:** $$\begin{array}{c|c|c} & s & s \\ \hline S & Ss & Ss \\ s & ss & ss \\ \end{array}$$ 5. **Phenotypes:** - $Ss$ results in seeded oranges (since $S$ is dominant). - $ss$ results in seedless oranges. 6. **Probability:** - 50% offspring are $Ss$ (seeded). - 50% offspring are $ss$ (seedless). 7. **Answer:** The offspring will be 50% seeded oranges and 50% seedless oranges. This shows the heterozygous parent passes on either allele with equal probability, and crossing with a homozygous recessive reveals the genotype.