Which of the following most appropriately describes haemophilia?

Marriages between close relatives should be avoided because they have a higher incidence of:

$A$ colour-blind son will be born when:

$A$ colour blind man marries a female with homozygous normal vision. What will be the possibility of colour blindness in their male children?

$A$ man with normal vision whose father was colourblind marries a woman whose father was also colourblind. Suppose their first child is a daughter,what are the chances of this child being colourblind (in $\%$)?

In a practical examination, the pedigree chart shown below was provided for identification. Identify the type of inheritance.