Presbyopia is a type of far-sightedness.

$A$ student sitting on the last bench can read the letters written on the blackboard but is not able to read the letters written in his textbook. Which of the following statements is correct?

When white light is incident on a blue pigment,which colors of light are reflected?

What is the least distance of distinct vision of a normal human eye (in $cm$)?

With the help of scattering of light,explain the reason for the difference in colours of the Sun as it appears during sunrise/sunset and noon.

What is the function of the choroid?