Final answer:
The image height of the print on the retina is -0.233 mm, which enables the distinction of letter details against the smaller rods and cones in the fovea.
Step-by-step explanation:
The student's question involves calculating the image height of print on the retina when a book is held 30 cm away from the eye, with the original print height being 3.50 mm. This question falls under Physics, as it relates to optics and image formation. Using the principles of lens and magnification, we can calculate that the image height on the retina is -0.233 mm. Furthermore, when comparing this to the sizes of rods and cones in the fovea, which are involved in visual perception, we note that the cones especially, which are responsible for high acuity vision, are smaller than the image height, allowing for the discrimination of details like letters on a page.