In a dihybrid cross with 9:3:3:1 ratio of offspring, what fraction shows both recessive traits?
A9 of 16
B3 of 16
C1 of 16
D1 of 4
Answer & Solution
Correct answer: C. 1 of 16
1. A dihybrid F₂ generation has 16 equally likely outcomes from the Punnett square.
2. The 9:3:3:1 phenotypic ratio groups them by visible features.
3. The number 9 corresponds to both dominant traits being expressed.
4. The two 3s each correspond to one dominant and one recessive trait.
5. The number 1 corresponds to both recessive traits expressed.
6. So one out of sixteen offspring shows both recessive traits.
_Source: NCERT Class 10 Science Ch 9 'Heredity' (learncbse.in extract)_
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