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.

1. Kala-azar disease is caused by the protozoa Leishmania donovani.

2. It is a parasitic protozoa that belongs to the class Mastigophora or Flagellata. It is caused by sand fly (Phlebotomus) which causes kala azar or dumdum fever.

The botanical name of the mango is Mangifera indica. It is a species of flowering plant in the sumac and poison ivy family, Anacardiaceae. Mangoes are widely cultivated for their edible fruit and are native to South Asia but are now grown in many parts of the world.