<Li> Cone monochromacy is a rare total color blindness that is accompanied by relatively normal vision, electroretinogram, and electrooculogram . Cone monochromacy can also be a result of having more than one type of dichromatic color blindness . People who have, for instance, both protanopia and tritanopia are considered to have cone monochromacy . Since cone monochromacy is the lack of / damage of more than one cone in retinal environment, having two types of dichromacy would be an equivalent . </Li> <Li> Dichromacy is hereditary . Protanopia and deuteranopia are hereditary and sex - linked, affecting predominantly males . <Ul> <Li> Protanopia is caused by the complete absence of red retinal photoreceptors . Protans have difficulties distinguishing between blue and green colors and also between red and green colors . It is a form of dichromatism in which the subject can only perceive light wavelengths from 400 up to 650 nm, instead of the usual 700 nm . Pure reds cannot be seen, instead appearing black; purple colors cannot be distinguished from blues; more orange - tinted reds may appear as dim yellows, and all orange - yellow - green shades of too long a wavelength to stimulate the blue receptors appear as a similar yellow hue . It is present in 1% of males . </Li> <Li> Deuteranopia affects hue discrimination in a similar way to protanopia, but without the dimming effect . Again, it is found in about 1% of the male population . </Li> <Li> Tritanopia is a very rare color vision disturbance in which only the red and the green cone pigments are present, with a total absence of blue retinal receptors . Blues appear greenish, yellows and oranges appear pinkish, and purple colors appear deep red . It is related to chromosome 7; thus unlike protanopia and deuteranopia, tritanopia and tritanomaly are not sex - linked traits and can be acquired rather than inherited and can be reversed in some cases . </Li> </Ul> </Li> <Ul> <Li> Protanopia is caused by the complete absence of red retinal photoreceptors . Protans have difficulties distinguishing between blue and green colors and also between red and green colors . It is a form of dichromatism in which the subject can only perceive light wavelengths from 400 up to 650 nm, instead of the usual 700 nm . Pure reds cannot be seen, instead appearing black; purple colors cannot be distinguished from blues; more orange - tinted reds may appear as dim yellows, and all orange - yellow - green shades of too long a wavelength to stimulate the blue receptors appear as a similar yellow hue . It is present in 1% of males . </Li> <Li> Deuteranopia affects hue discrimination in a similar way to protanopia, but without the dimming effect . Again, it is found in about 1% of the male population . </Li> <Li> Tritanopia is a very rare color vision disturbance in which only the red and the green cone pigments are present, with a total absence of blue retinal receptors . Blues appear greenish, yellows and oranges appear pinkish, and purple colors appear deep red . It is related to chromosome 7; thus unlike protanopia and deuteranopia, tritanopia and tritanomaly are not sex - linked traits and can be acquired rather than inherited and can be reversed in some cases . </Li> </Ul> <Li> Protanopia is caused by the complete absence of red retinal photoreceptors . Protans have difficulties distinguishing between blue and green colors and also between red and green colors . It is a form of dichromatism in which the subject can only perceive light wavelengths from 400 up to 650 nm, instead of the usual 700 nm . Pure reds cannot be seen, instead appearing black; purple colors cannot be distinguished from blues; more orange - tinted reds may appear as dim yellows, and all orange - yellow - green shades of too long a wavelength to stimulate the blue receptors appear as a similar yellow hue . It is present in 1% of males . </Li>

Can a human male be a carrier of red-green color blindness why or why not