Answer:
This question lacks options, the options are:
A. All 270 tall plants were heterozygous
B. All 270 tall plants were homzygous.
C. Only 90 plants were homzygous.
D. All dwarf plants were homzygous.
The answer is D.
Explanation:
This question involves a single gene coding for height in pea plants. The allele for tallness (T) is dominant over that of dwarfness (t). This means that a dwarf plant can only be homzygous recessive (tt) while a tall plant can either be homzygous (TT) or heterozygous (Tt).
According to the question, two tall heterozygous pea plants were crossed i.e. Tt × Tt. Based on this cross, a phenotypic ratio of 3:1 is expected, which is in accordance with the 270 tall plants and 90 dwarf plants (360 total) that was obtained in the cross. Since dwarfism in pea plants is a recessive trait, this means that all the dwarf plants produced in this cross (90) were homzygous (tt).
