Man is normal while women of colourblind mother is also colourblind. The gene for colour blindness is present on $X$-chromosome as a recessive autosomal diseases. One $X$-chromosome from mother goes to daughter and other to son while the X-chromosome of father (Normal) goes to daughter and $4 $ chromosome to son.
Mendelian Disorder is a type of genetic disorder that is caused due to alterations in one gene or abnormalities in the genome. These disorders can be seen since birth and can be deduced using the Pedigree Analysis.