1. Zachary was born with a rare visual defect. He has no cone photoreceptors in his retina, there are only rods. Assuming that all other aspects of his visual system are normal, which of the following would characterize Zachary's vision? A) poor visual acuity B) an inability to differentiate between black and white C) a difficulty seeing in low light conditions D) colour blindness E) both A) and D)
