Which of the following features are correct regarding Law of Dominance?
A. In a dissimilar pair of factors one member of the pair dominates the other.
B. In a similar pair of factors one member of the pair dominates the other.
C. Characters are controlled by discrete units called factors.
D. Characters are controlled by undiscrete units called factors.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → A and C only
From his monohybrid crosses, Mendel gave two laws. The first is the Law of Dominance. It has three points: characters are controlled by discrete units called factors; factors occur in pairs; and in a dissimilar pair of factors, one member (the dominant) dominates the other (the recessive). This law explains why only one parental character shows in the F1 generation.
A. In a dissimilar pair of factors one member of the pair dominates the other. — Correct. This is the central point of the law. In a pair like Tt, T is expressed and t is hidden.
B. In a similar pair of factors one member of the pair dominates the other. — Incorrect. In a similar pair (TT or tt), both factors are the same, so there is nothing for one to dominate.
C. Characters are controlled by discrete units called factors. — Correct. Mendel said a character is controlled by separate, distinct units, the factors. Today we call them genes.
D. Characters are controlled by undiscrete units called factors. — Incorrect. The factors are discrete (separate) units. They do not blend with each other.
NCERT Extract:
Law of Dominance –
