1. Which plane mirror is used to make periscope?

2. An optical instrument used to see through an object that is occluded from the direct line of sight is called a periscope.

3. A periscope consists of two plane mirrors placed at an angle of 45°.

4. When light falls on one of the mirrors then after reflection from the first mirror it falls on the second mirror which further reflects it and falls on the eye of the observer.

Cats (and many other animals) have a layer of cells behind their retinas called the tapetum lucidum. This layer enhances night vision by reflecting light that passes through the retina back into the eyes. When light enters the eye, some of it is absorbed by the retina's cells, allowing the brain to process visual information. However, the tapetum lucidum reflects the remaining light back through the retina, giving the photoreceptor cells a second chance to detect the light. This reflection of light enhances their night vision capabilities and is what causes a cat's eyes to appear to glow in the dark or in low light conditions.

Epithelial tissue plays a crucial role in wound healing. When the skin is wounded, epithelial cells at the edges of the wound multiply and migrate to cover the wound, forming a protective layer. This process is essential for the initial sealing of the wound and is one of the early stages in the overall wound healing process. Epithelial tissue helps in closing the wound and restoring the skin's integrity.