Questions

Troposphere is the most densest layer and is the lowest atmospheric layer.

Laterite soils are a tropical soil and possess a great amount of iron and aluminum. Due to its high iron oxide content they look like rusty-red coloration.

From the cornea, the light passes through the pupil. From there, it then hits the lens, the transparent structure inside the eye that focuses light rays onto the retina. The iris, or the colored part of your eye, regulates the amount of light passing through. 

The size of the pupil is controlled by the Iris when light enters the eye.

Androgens such as testosterone are produced by the Interstitial cells.