A person may have one gene for normal haemoglobin and one gene for sickle cell haemoglobin. This heterozygous condition is called

A husband and wife have normal vision but fathers of both of them were colour blind. Probability of their first daughter to be colour blind is

If a man who is colour blind marries a women, who is pure normal for colour vision, the chances of their sons have colour blindness is

Disorder inherited as Mendel's law of inheritance called

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