# The physical structure of the human eye enables it to sense light of wavelengths up to 0.0005 millimeters; infrared radiation, however, is invisible because its wavelength—0.1 millimeters—is too long to be registered by the eye.

The physical structure of the human eye enables it to sense light of wavelengths up to 0.0005 millimeters; infrared radiation, however, is invisible because its wavelength—0.1 millimeters—is too long to be registered by the eye.

A. infrared radiation, however, is invisible because its wavelength—0.1 millimeters—is too long to be registered by the eye

B. however, the wavelength of infrared radiation—0.1 millimeters—is too long to be registered by the eye making it invisible

C. infrared radiation, however, is invisible because its wavelength—0.1 millimeters—is too long for the eye to register it

D. however, because the wavelength of infrared radiation is 0.1 millimeters, it is too long for the eye to register and thus invisible

E. however, infrared radiation has a wavelength of 0.1 millimeters that is too long for the eye to register, thus making it invisible

In-depth Explanation and Correct Answer Below (so you don’t see it while reviewing the question)

## The physical structure of the human eye… Explanation

The physical structure of the human eye enables it to sense light of wavelengths up to 0.0005 millimeters; infrared radiation, however, is invisible because its wavelength—0.1 millimeters—is too long to be registered by the eye.

(A) infrared radiation, however, is invisible because its wavelength—0.1 millimeters—is too long to be registered by the eye

(B) however, the wavelength of infrared radiation—0.1 millimeters—is too long to be registered by the eye making it invisible

Wrong subject: the wavelength of infrared radiation. The main subject should be the infrared radiation itself. Is the wavelength invisible or the radiation? This option points to the wavelength. Also, the “it” is ambiguous. Does it refer to the wavelength or the radiation?

(C) infrared radiation, however, is invisible because its wavelength—0.1 millimeters—is too long for the eye to register it

What is the “it” at the end? Fill in all of the possible singular nouns.

(D) however, because the wavelength of infrared radiation is 0.1 millimeters, it is too long for the eye to register and thus invisible

Wrong subject: the wavelength of infrared radiation. The main subject should be the infrared radiation itself. Is the wavelength invisible or the radiation? This option points to the wavelength.

(E) however, infrared radiation has a wavelength of 0.1 millimeters that is too long for the eye to register, thus making it invisible

The “that” changes the meaning by talking about a specific .1 millimeter wavelength that is too long for the eye to register. Also, the “it” is ambiguous. Does it refer to the wavelength or the radiation?