题目选项分析

The physical structure of the human eye enables it to sense light of wavelengths up to 0.0005 millimeters; however because the wavelength of infrared radiation is 0.1 millimeters, it is too long for the eye to register and thus invisible.

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.