Final answer:
The ratio of tall to short plants in the second offspring generation (F2) when crossing two heterozygous tall pea plants (Tt) is 3:1, with three tall plants for every short plant.
Step-by-step explanation:
The ratio of tall to short plants that describes the second offspring generation, also known as the F2 generation, is a result of crossing two heterozygous tall pea plants. When these F1 generation plants (Tt) self-pollinate, the resulting offspring (F2) will have four possible combinations of these factors: TT, Tt, tT, and tt. By using a Punnett square, we can predict the resulting genotypic frequencies. The tt genotype results in short plants, and since one-fourth of the offspring would be tt, this means that there is a 25% chance of obtaining a short plant. The remaining three-fourths, or 75% of the offspring, will have at least one dominant allele (T), resulting in tall plants. Therefore, the phenotypic ratio of the F2 generation is 3 (tall):1 (short), corresponding to the option (c) 3:1 in the provided multiple-choice question.