Lack of independent assortment of two genes 'A' and 'B' in fruit fly Drosophila is due to 

 In garden pea , yellow colour of cotyledons is dominant over green and round shape of seed is dominant over wrinkled. When a plant with yellow and round seeds is crossed with a plant having yellow and wrinkled seeds, the progeny showed segregation for all the four characters. The probability of obtaining green round seeds in the progeny of this cross is  .

The gene, which controls many characters is called  

Genes are made up of 

When two hybrids rrTt and  Rrtt  are crossed, the phenotype ratio of offspring would be  .

Some individuals with blood group A may inherit the  genes for blond hair, while other individuals with blood group A may inherit the gene for brown hair. This can be best explained by the principle  of 

Genes exhibiting multiple effects are known as