Mendel proposed law of dominance and law of segregation based on his observations on

Options

A. Monohybrid crosses
B. Dihybrid crosses
C. Test crosses
D. Out crosses

Answer

### Step-by-Step Solution:

1. **Understanding Mendel's Work**: Gregor Mendel is known as the father of genetics. He conducted experiments on pea plants to understand how traits are inherited from one generation to the next.

2. **Identifying the Crosses**: Mendel performed several types of crosses, but the question specifically asks about the Law of Dominance and the Law of Segregation.

3. **Monohybrid Cross**: The correct answer is that Mendel proposed the Law of Dominance and the Law of Segregation based on his observations from a **monohybrid cross**. A monohybrid cross involves a single trait, where two parents differing in one characteristic are crossed.

4. **Law of Dominance**: This law states that when two different alleles are present in a genotype, one allele (the dominant allele) can mask the expression of the other allele (the recessive allele). In a monohybrid cross, this can be observed when one trait is expressed in the offspring while the other is not.

5. **Law of Segregation**: This law states that during the formation of gametes, the two alleles for a trait segregate from each other so that each gamete carries only one allele for each trait. This is also observable in the results of a monohybrid cross.

6. **Results of Monohybrid Cross**: In Mendel's experiments, he found that when he crossed tall pea plants (TT) with short pea plants (tt), the first generation (F1) consisted entirely of tall plants (Tt). When these F1 plants were self-fertilized, the second generation (F2) showed a phenotypic ratio of approximately 3 tall plants to 1 short plant.

7. **Conclusion**: Therefore, Mendel's observations from the monohybrid cross led to the formulation of the Law of Dominance and the Law of Segregation.