Question

Which of the following laws of genetics has been proved to be true in all cases?
(a) Law of segregation
(b) Law of independent assortment
(c) Law of dominance
(d) All of the above

Answer 1

Trait of offspring such as character, structure, function, and behavior depend upon the genetic combination of parents. In some organisms, the genetic combination doesn't show variation while some organism shows variation from generation to generation.

Complete Answer:
Law of dominance, the law of segregation and law of independent assortment are three main law of Mendel but only the law of segregation proved to be true in all cases because according to this law the two factors of characters does not show blending, so that gamete carries only one factor of character and is always pure.
In the case of segregation, the phenotypic and genotypic ratios both remain the same.

Additional information:
The Law of dominance states that out of two alleles that represent different traits of characters, only one expresses itself and the allele which expresses itself in hybrid is considered as a dominant allele. According to this law in the case of hybrid only dominant alleles express themselves while recessive does not. This law proves itself only in the case of a monohybrid cross because in a dihybrid cross both parent alleles express themselves in offspring. In the case of codominance, both genes are dominant and both express themselves because the recessive allele does not contain any enzyme therefore it does not show blending.
According to the law of independent assortment, an allele of different characters separates independently of one another at the time of gametogenesis and sporogenesis by which the gamete rearranged in offspring at the time of fertilization. This law is applicable only to those genes located on a different chromosome. Linked genes violate this law that's why this law does not prove itself in all cases.

So, the correct answer is the ‘Law of segregation’.

Note: The Mendel experiment only gave a successful result in the case of pea plants because of pure breeding varieties. Mandela investigated only those characters where the opposing trait was well developed and the sampling size is large.