(i) Solar power is the conversion of energy from sunlight into electricity either directly using photovoltaic cells or indirectly using concentrated solar power.
(ii) Solar panels absorb the sunlight as a source of energy to generate electricity.
(iii) A solar electric system can reliably produce electricity for our home and offices.

(i) Human resource is necessary for the progress of any country.
(ii) It refers to the collective abilities of people which can be utilised in the production sector.
(iii) It is invested with good education and health.
(iv) Therefore investment in education and health can result in a high rate of returns in the future.

(i) The Net National Product (NNP) is considered as a true measure of national output. It is also known as national income.
(ii) A rise in per capita income means an increase in aggregate real output. Hence, this is a better indicator than national income for measuring development.
(iii) For measuring a country's development, its income is considered to be one of the most important factors. Countries with higher income are considered to be more developed than those with lesser income.
(iv) So, income itself is considered to be one of the indicators of economic development.

Sustainable economic development is taken to mean development without damaging the environment and not compromising with the needs of the future generation. The consequences of environmental degradation do not respect national or state boundaries. Sustainability of development is comparatively a new area of knowledge in which scientists, economists, philosophers and other social scientists are working together. Natural resources can be divided into renewable resources and non-renewable resources. Groundwater is an example of a renewable resource. The question arises as to how sustainable development is possible if the resources are over-used rather than getting replenished. Nonrenewable resources get exhausted after certain number of years of extracting and using them and they cannot be replenished. To achieve real sustainability, we need to balance economic, social and environmental sustainability in equal harmony. In general, the question of development or progress is continuous. At all times, as a member of society and as individuals, we need to ask where we want to go, what we wish to become and what our goals are.

In my locality i found the following environmental problems:
1. Air pollution: As there are a number of vehicles in my area the air pollution in very high Whenever I walk on the road, I could smell the carbon dust emitted from the vehicle.
2. Water pollution: Previously we could get clear water from our taps. Now the water is muddy and polluted.
3. Soil Pollution: Because of the incrase of air pollution we could find the soil polluted in our area.

(i) Development increases the quality of life.
(ii) People will have higher incomes, better education, better health and nutrition, less poverty and more equality of opportunity.

If a child is invested with good education and health, he or she may turn to be very productive in future in the form of higher earnings and greater contribution to the society. Therefore that. investment in education and health of people can result in a high rate of returns.

Human Resource Development means the development of a person's physical and mental abilities through education, health care and training.

Since the countries have different populations comparing total income will not be suggestive of what an average person is likely to earn. So, for comparing the development of various countries total income is not an useful measure.