Laws of inheritance - class-XII

In a cross AABBCC x aabbcc, all F1 progeny will be AaBbCc. Since all individuals have the same genotype, they will all express the same phenotype.

Discovery of mendels law of segregation required the use of parental crosses with true breeding plants followed by crosses with f1 heterozygous plants.

Mendel worked with the garden pea, which has 14 chromosomes and 7 linkage groups, corresponding to the 7 traits he studied. If he had used a species with only 4 chromosomes, the number of linkage groups would be fewer than the 7 characters studied, meaning some characters would show linkage and fail to assort independently.

In the given question the number of the heterozygous gene pair is 3 so the number of phenotypes will also be 3.

Mendel's law of independent assortment states that allele pairs separate and segregate independently of one another during the formation of gametes. So, traits are transmitted to offspring independently of one another and recombinants are seen along with the parental types in the genotype of the next generation. So, progeny can have a new combination of traits that are not seen in either parent. So, the correct option is 'Law of independent assortment'.

The law of dominance is significant and true but is not universally applicable. Only Law of independent assortment and Law of segregation are considered to be laws. The third one is considered as a basic principle but not a genetic law of Mendel. Therefore, (a) is the correct answer.

As per linkage experiments carried out by Morgan, the two linked genes do not always segregate independently of each other and $F _2$ ratio deviated very significantly from 9:3:3:1 ratio (expected when two genes are independent). Hence, if linkage was known at the time of Mendel, he would riot have been able to explain law of independent assortment. 

Some alleles are dominant while others are recessive. Organism with at least one dominant allele will display the effect of the dominant allele, which is studied under Law of dominance. Therefore, (b) is the correct answer.

Ratio is totally deviated from 3(red) : 1 (white), Hence this is a case of mutation which is resulting into this outcome.

Statement A correctly describes the law of segregation, stating that alleles remain pure and unmixed in hybrids. Statement C correctly notes that each gamete receives a factor determining a single trait. Statement B describes independent assortment, and statement D describes incomplete dominance, neither of which is part of the law of purity of gametes.

Genes for different traits can segregate independently during the formation of gametes. This is the result of Law of independent assortment which was studied Mendel. Therefore, (C) is the correct answer.

During gamete formation, the alleles for each gene segregate from each other so that each gamete carries only one allele for each gene. This was proposed in the Law of segregation. Therefore, (b) is the correct answer.

Mendel's law of Segregation: The principle of segregation describes how pairs of gene variants are separated into reproductive cells. The segregation of gene variants, called alleles, and their corresponding traits was first observed by Gregor Mendel in 1865. Mendel was studying genetics by performing mating crosses in pea plants.
Each gamete receives one gene for an allele and thus, is haploid in nature. Both male and female gametes, which are haploid will fuse and forms a diploid zygote.

The modern synthesis reconciled Mendelian genetics with Darwinian evolution by showing that population genetics (a) and the understanding of genetic variation through recombination (c) provide the mechanism for natural selection.