.A small, cold creek flows through a dense forest. The trees line the banks of the creek providing shade most of the day. Algae grow well only in a few areas of the creek that receive direct sunlight. Most of the food energy enters the ecosystem in the form of dead leaves that fall from the trees. A fire swept through the forest, burning all the leaves, but leaving the trees standing. This increased the amount of direct sunlight reaching the creek. As a result of the fire, what increased in the creek? What type of succession will occur to open new available niches and resources?

People with normal vision cannot focus their eyes underwater if they aren't wearing a face mask or goggles and there is water in contact with their eyes. in a simplified model of the human eye, the aqueous and vitreous humors and the lens all have a refractive index of 1.40, and all the refraction occurs at the cornea, whose vertex is 2.60 cm from the retina.with the simplified model of the eye, what corrective lens (specified by focal length as measured in air) would be needed to enable a person underwater to focus an infinitely distant object? (be careful-the focal length of a lens underwater is not the same as in air! assume that the corrective lens has a refractive index of 1.62 and that the lens is used in eyeglasses, not goggles, so there is water on both sides of the lens. assume that the eyeglasses are 2.05cm in front of the eye.)