- Total death in a specific year/total population in that year multiple by 1000 is called “Crude Death Rate”.
- Crude death rate is also known as “Mortality Rate”.
- Number of births per 1000 is called “Reproduction Rate”.
- The maximum number of year that an individual could live is called Lifespan.
- Fuel form under the earth’s surface by the decomposition of organic matter is called fossil fuel.
- Coal causes the least pollution when burnt.
- The sun, wind and ocean tidal energy are renewable source of energy.
- A solar cell is made up of silicon.
- A solar cell converts solar energy into electrical energy.
- The fuel used in the nuclear reactor is Uranium.