The idea that psychology should be based only on observable, measurable behaviors is central to ______

Vascular dementia (VaD) is caused by a series of ______

Fill in the blank with correct word

A fifty-something mom says, "I can't see well in the dark, and I can't see anything close up." The reason is that, by this age, the _____ of the eye gets cloudier and can't bend well.

A) lens B) cornea C) retina D) pupil