Select from the following a group of birds each member of which is able to see distinctly the object four times as far as we can see.

The correct option is Eagles, Kites, Vultures.

Some birds of prey, such as eagles, kites, and vultures, have specialized vision that allows them to see objects from a distance four times greater than humans can. For example, an object that a human can clearly see from a distance of 2 meters can be clearly seen by these birds from a distance of 8 meters.

This powerful eyesight is due to several structural adaptations in their eyes:

1. Foveal Density: They have a higher concentration of photoreceptor cells (cones) in their retina, providing much higher visual acuity and sharp focus over long distances.

2. Double Fovea: Unlike humans who have a single fovea per eye, these birds possess two foveae (monocular and binocular vision regions), allowing them to perceive depth while maintaining a wide field of view.

3. Larger Eyes relative to body size: Their eye structure allows more light to enter and forms a larger, clearer image on the retina.