Red green colour blindness appears due to
Excessive drinking of alcohol
Inheritance through $X$ chromosome
Over activity of adrenal
Vitamin $A$ deficiency
In pedigree analysis, the square, blackened and horizontal lines represents
Among symbol $A, B$ and $C, C$ indicates
Persons who are colour blind cannot distinguish
Sickle -cell anaemia has not been eliminated from the African population because it
Following characters are indicate
$(i)$ presence of sickle - shaped $RBC$
$(ii)$ Blood not clot, non stop bleeding
$(iii)$ The heterozygous female transmit the disease to sons.
$(iv)$ Both heterozygous parents transmit the disease to offspring