Colorblindness is a vision deficiency that limits the ability of the

OFFICIAL EXPLANATION

Overview:

Question gives information about the vision deficiency known as colorblindness, wherein sufferers have varying degrees of an inability to distinguish color. The author explains that colorblindness is believed to originate from a mutation of the X chromosome. The author also states that men have an XY chromosome makeup, while women have an XX chromosome makeup. The question asks for a statement that may be inferred from the passage, based on the information contained within it.

The Correct Answer:

D At the end of the passage, the author notes, “Men carry a single X chromosome, possessing an XY-chromosome makeup, while women carry two X chromosomes, thus having the potential to combat colorblindness with an extra X chromosome.” This suggests that men are more likely to be colorblind than women because men have only a single X chromosome. Of all the answer choices, answer choice (D) can best be inferred from the passage, so it is correct.

The Incorrect Answers:

A The author makes no comment on the population percentage of colorblindness sufferers, so it is impossible to infer safely that colorblindness is a rare condition. The student might know from prior knowledge that colorblindness is a fairly rare condition, but the question asks for what can be inferred from the passage, not what the student already knows to be true. As answer choice (A) cannot be inferred, it cannot be correct.

B Again, the information contained within answer choice (B) might well be true, but it cannot be inferred from the passage. The author notes only that colorblindness “limits the ability of the sufferer to see certain colors clearly. The condition may affect a person in varying degrees, ranging from mild colorblindness with a red or green color deficiency to complete colorblindness with no ability to distinguish any colors beside dim shades of brown.” This in itself does not suggest clearly that colorblindness sufferers would be able to see camouflage well, so answer choice (B) is incorrect.

C The author does not discuss the way that colorblindness is passed on, much less the fact that colorblindness is a hereditary condition. Although the author does imply that women are less likely to be colorblind than men, the author does not necessarily imply that women alone pass the condition on.. Answer choice (C) cannot be inferred from the passage, so it is incorrect.

E As with answer choice (C), the author does not discuss whether colorblindness is an inherited condition. So, it is impossible to determine from the passage if the author also believes that colorblindness can be tested at birth. Answer choice (E) infers details that are not supported by the passage, so it is incorrect