Answer: Race
Explanation: Race is a heritage that various and diverse group of people use to identify with each other. Race may include physical characteristics such as the skin color example the black race and other associated traits such as facial features and hair texture
It is called ACCOMMODATION. Accommodation refers to the mechanism by which the eye adjusts his optical power in order to focus properly on an object as the distance of the object varies. To achieve this, the shape of the lens has to be adjusted appropriately.
I would say that it is B. thinner.