Which type of color deficiency is characterized by the inability to distinguish between red and green?

The correct answer identifies that both protanopia and deuteranopia are types of red-green color deficiencies. Protanopia involves a lack of red photoreceptors, leading individuals to confuse reds and greens, while deuteranopia involves a lack of green photoreceptors, causing similar difficulties.

Tritanopia, on the other hand, is characterized by a deficiency in blue-yellow color discrimination rather than red-green. It affects the ability to distinguish between blue and yellow hues.

Thus, the correct response reflects that protanopia and deuteranopia share the characteristic of red-green confusion, whereas tritanopia does not. The grouping of options in the answer indicates that protanopia and deuteranopia specifically result in the inability to distinguish between red and green hues, confirming that the acknowledgment of red-green color deficiencies is accurate.