Which one of the following symbols and its representation, used in human pedigree analysis is correct?

A boy is colour blind, in his two sisters one is colour blind and one is carrier $(normal)$. Then who is colour blind in his family

Select the correct match.

Sickle­cell anaemia is

Colour blindness is a disease usually affecting man but the factor for it is transmitted to the children always by woman. This is because particular factor is located on

Thalassemia and sickle cell anaemia are caused due to a problem in globin molecule synthesis. Select the correct statement.