Brian has a medical condition called cone dystrophy, which is a disorder of the cone cells in the eye. what symptoms would you expect brian to have?

inability to see in the dark
difficulty determining colors
difficulty determining shapes and outlines
inability to see in all light conditions

The correct answer is "difficulty determining colors".

Explanation:

Cone dystrophy is a medical condition that affects the cone cells of the retina. Cone cells help a person to see colors and fine details. Cone cells work best in light conditions. One with cone dystrophy can experience a variety of symptoms such as inability or reduced ability to see colors, an increase in sensitivity for light and others.

So, the best answer is difficulty determining colors.

you know they are heterozygous for a trait because they have it as jj or jj.