If a person lacks green cones in the retina, she or he has difficulty distinguishing between which colors?

Answer 1

http://www.toledo-bend.com/colorblind/aboutCB.html
Go to this site and scroll down to Clinical Information and it will explain about the cones in the retina.

Answer 2

Cones come in three varieties: red, blue, and green. Red light stimulates the red cones, and simultaneously inhibits the surrounding green cones. Green light does the exact opposite (green and red are each other's opponent colors). Blue light stimulates the blue cones and inhibits both red and green cones (red and green light, mixed, form yellow light -- blue's opponent color).

There are many other versions of colorblindness, but by far the most common is red-green colorblindness, which affects as many as one out of 25 people. These people either do not have red cones (protanopia) or green cones (deuteranopia). They are unable to distinguish between green and red, but with their remaining two types of cones are able to see all of the other colors. The absence of blue cones is extremely rare.

Answer 3

They are classified as color blind and can only see black and white.