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🔬 Biology  ·  Principles of Inheritance and Variation  ·  NEET

In a monohybrid cross between two Aa parents, ratio of phenotypes in F<sub>2</sub>:

Answer: 3:1 dominant:recessive.

  • A 3:1 dominant:recessive
  • B 1:2:1 ratio as seen in incomplete dominance
  • C 1:1 ratio as seen in a test cross
  • D All offspring showing the dominant phenotype

Correct answer: A. 3:1 dominant:recessive

Explanation: Aa x Aa → 1 AA : 2 Aa : 1 aa. Phenotype: 3 dominant (AA + 2 Aa) : 1 recessive (aa). Classic 3:1 ratio.

Monohybrid Cross: Tt x TtParent 1 (Tt)Parent 2 (Tt)gametes: T, t (from each parent)TtTtTTTtTtttRatio 1 TT : 2 Tt : 1 tt (3 tall : 1 short if T = tall is dominant)

Punnett square for a monohybrid cross between two heterozygous (Tt) parents, showing the 3:1 phenotypic ratio predicted by Mendel's Law of Segregation.

Concept context

Mendel's laws, inheritance patterns, DNA structure, and molecular biology. Core of NEET biology.

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