Why is a normal eye not able to see clearly the objects placed closer than 25 cm?
Answer
A normal eye can see objects kept at various distances clearly due to the ability of the ciliary muscles to increase or decrease its focal length of the eye lens.
We cannot see the objects closer than 25 cm because the ciliary muscles are unable to contract after a certain limit.
Hence, the object closer than 25 cm appears blurred because light rays coming from the object meet beyond retina.