The right answer is C.invention
Contact lenses are placed directly on the surface of the eye to correct your eyesight.
They can correct myopia and hyperopia. They can also correct age-related astigmatism and hyperopia (presbyopia).
Their principle is the same as for glasses: they bend the light and redirect it to your retina to improve your eyesight.
Natural resources are the things that are present in nature right now. Ecosystem capital is when corporations use those resources to make a profit; profit meaning to sale things for an unreasonable amount.
Good luck!
Short answer - to breathe.
Long answer - the black streaks on the trunk of birch trees are called lenticels, and their function is to enable the exchange of gases between the tree and the air. So, in a way, this makes the whole process of photosynthesis a lot easier for birch trees.
The answer is A. random gene pool changes in small population.
