When Mendel crossed short (tt) pea plants with short (tt) pea plants, what was the genotype of all the offspring?

• A. All offspring were homozygous recessive (tt)
• B. Half the offspring were tall and half were short
• C. All offspring were homozygous dominant (TT)
• D. All offspring were heterozygous (Tt)

Answer: (A)

Verified step by step guidance

1. Identify the genotypes of the parent plants. Both parents are short pea plants with genotype \(tt\), meaning they are homozygous recessive.
2. Recall that each parent can only contribute one allele to the offspring. Since both parents are \(tt\), each parent contributes a \(t\) allele.
3. Determine the possible genotypes of the offspring by combining the alleles from each parent. The only possible combination is \(tt\).
4. Understand that \(tt\) genotype corresponds to the short phenotype because \(t\) is the recessive allele for shortness.
5. Conclude that all offspring will be homozygous recessive (\(tt\)) and therefore short, with no variation in genotype or phenotype among the offspring.