Adjustment knobs are used to focus light in a light microscope
That is true. Active transport goes against the concentration gradient. Particles want to move from higher concentration to lower concentration and even out, but active transport makes them move against that.
The function of microviilli is to absorb nutrients in the small intestine to absorb nutrients that were not absorbed in the small intestine...
Protection of certain species is a very controversial topic. Many species like the mountain lion or jaguar that are near extinction in certain areas, are threats to human life. Another reason is that they could off set the food chain when they come back and be stonger than ever. For example the mountian lion could eat out the thriving white tail deer population which was struggling because of the mountain lion. And many people rely on white tail deer for food.
Hope this helped :)
