Anything from which we can derive energy is called as a source of energy. Since all the life processes need energy, energy is most important for our survival. Our body derives energy from the food we eat. Thus, the food we eat is the source of energy for our body. But this is not the whole story. We need energy for our growth and economic development as well.
The digested food is absorbed into the body from where it is distributed to all its cells.
Birds that travel from one place to the other place are called as Migratory Birds.
Fossil fuels- coal, petroleum and natural gas, are sources of energy and lots of useful substances. They have been and still they are the back bones of the economic developments and the basis of the modern civilization.
Green plants and trees that synthesize their own food are called as Autotrophs.Others who depend on them are called as Heterotrophs.
Man has been keeping animals and depending on them for his livelihood since the origin of civilization. Washermen have been depending on donkeys since long for carrying clothes.
Mixing of different solid, liquid or gaseous substances and microorganisms into water, so as to alter its natural qualities is called as water pollution. According to the National Water Commission (1973), water gets polluted if it has not been of sufficiently high quality to be suitable for the highest uses people wish to make of it at present or in future.
An activity that serves as one’s regular source of livelihood is called as occupation
Ocean is a vast natural resource of water. These have also been examined in the search for alternate sources of energy-generation. For example, gravitational pull, by sun and moon causes tides, in which sea level rises and falls, two times in 24 hours. When it rises, sea water may be diverted through suitable channels, to inshore reservoirs driving the turbines, during its entry.
Energy is essential for working and survival of all the organisms on this planet. In fact, it is the energy which enables organisms to perform their biological functions.
People who suffer from hunger remain undernourished. They don’t get enough food to eat. As such they don’t get energy, they need to live active lives. Undernourished persons remain unable to study, work or otherwise perform physical and mental activities. This condition is especially hard for women and children. Continuous hunger weakens the immune system and makes them vulnerable to diseases and infections. Mothers who suffer continuous hunger often give birth to underweight and weak babies, and they face increased risk of death.
