The Hardy - Weinberg Principle says:(A) Allele frequency in a populat…

The correct answer is Option (1) → (A), (C) and (D) only

The Hardy-Weinberg principle says that, in a population with no disturbing factors, allele frequencies do not change from one generation to the next. It is written as p² + 2pq + q² = 1, where p and q are the frequencies of the two alleles.

(A) Allele frequency in a population is stable and constant. — Correct. This is the principle itself.

(B) Allele frequency in a population is unstable. — Incorrect. It states the opposite of the principle. Frequencies change only when factors such as gene flow, genetic drift, mutation, recombination or natural selection act.

(C) The gene pool remains constant. It is called genetic equilibrium. — Correct. A constant gene pool is genetic equilibrium.

(D) The sum total of all the allelic frequencies is 1. — Correct. p + q = 1, and so p² + 2pq + q² = 1.

NCERT Extract:
Hardy-Weinberg Principle – “In a given population one can find out the frequency of occurrence of alleles of a gene or a locus. This frequency is supposed to remain fixed and even remain the same through generations. Hardy-Weinberg principle stated it using algebraic equations. This principle says that allele frequencies in a population are stable and is constant from generation to generation. The gene pool (total genes and their alleles in a population) remains a constant. This is called genetic equilibrium. Sum total of all the allelic frequencies is 1.”