1. What do you mean by terrarium?
Terrarium is an artificial enclosure for keeping small house plants.
2. Why do swimmers float in Dead Sea?
Swimmers float in dead sea because the increased salt content makes it dense.
3. How are clouds formed?
The sun's heat causes evaporation of water. When the water vapour cools, it condenses and forms clouds.
4. What are waves?
When the water on the surface of the ocean rises and falls alternately, they are called waves.
5. What is salinity?
Salinity is the amount of salt in grams present in 1,000 grams of water.
6. When is the World Water Day celebrated?
The World Water Day is celebrated on March 22.
7. What are the major sources of fresh water?
The major sources of fresh water are the rivers, ponds, springs and glaciers.
8. State one difference between’ waters of ponds and lakes’ and ‘ocean water’.
The water of ponds and lakes is calm, but ocean water keeps moving continuously. It is never still.