Your biology instructor has assigned you a lab exercise to test a hypothesis regarding the inheritance of stem length in pea plants. If your assignment is specifically to conduct a monohybrid cross for stem length from available genotypes growing in the lab, which of the following crosses should be performed?

A. Tt with tt

B. Tt with tt

C. Tt with TT

D. Tt with Tt

E. TT with TT

D. Tt with Tt

Explanation:

In the given question, the student wants to study the stem length in the plants which are controlled by the T (dominant) and t (recessive) alleles.

To study the monohybrid cross for the stem length, the student must cross the heterozygous forms of the gene for the trait as it will produce the mixture of variables of height.

cross - Tt x Tt

T t

T TT Tt

t Tt tt

1. Genotype TT - tall height

2. Genotype Tt - tall height

3. Genotype tt - small height

Thus, Option-D is correct answer.