Answer:
A cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides the cell with both structural support and protection, and also acts as a filtering mechanism.
Explanation:
A cell wall is a rigid, semi-permeable protective layer in some cell types. This outer covering is positioned next to the cell membrane (plasma membrane) in most plant cells, fungi, bacteria, algae, and some archaea.
A keystone species helps define an entire ecosystem. Without its keystone species, the ecosystem would be dramatically different or cease to exist altogether.
Answer: Light Refraction
Explanation:
Light rays travel in straight lines. When they strike an opaque surface, the rays bounce, and light is reflected back to your eye so that you see an image. When light strikes a transparent object, some of the light passes through. If that light strikes the object straight on, it continues to travel in a straight line. If the light enters the transparent object at an angle, though, it changes direction, bending.This bending of light is called refraction. Refraction occurs because light entering an object slows down. When it enters at an angle, one side of the light ray enters before the other, slowing down first.Looking from above, an object under water appears larger than it does in air. It's not that the image the light gave our eyes is bigger. It's that the image is actually closer to our eyes, since the light is not passing straight down, but is instead bending relative to the water's surface. Light passing straight down would be perpendicular to the water's surface, like the vertical line on the letter T.
