A and R are correct and R explains A

(i) incorrect
(ii) incorrect
(iii) is correct
(iv) incorrect

(a) The concept 'survival of the fittest' contributed to the scientific understanding of human origins.

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) Limestone is made up of Calcium Carbonate.
(ii) It dissolves in water easily.
(iii) So during rainfall the water at the joints and fractures of the limestone seeps easily underground.
(iv) So the underground water is more common than the surface run off.

Based on the periodicity of eruptions, volcanoes are classified into
(i) Active volcano,
(ii) Dormant volcano,
(iii) Extinct volcano.
(i) Active Volcano: Active volcanoes are those which constantly eject volcanic lava,gases and fragmented materials. (e.g.) Mount St. Helens in the United States.
(ii) Dormant Volcano: Volcanoes that do not show any sign of volcanic activity for a long period of time are known as dormant volcanoes. Sometimes there may be a sudden explosion which may cause unimaginable loss to life and property (e.g.) Mt. Fuji, Japan.
(iii) Extinct or Dead Volcano: When a volcano permanently stops its volcanic activity, then it is called as extinct or dead volcano (e.g.) Mt. Kilimanjaro, Tanzania.
Volcanoes can also be classified based on their structure and composition as composite volcano, shield volcano and dome volcano.

(i) Elected representatives of people and final decision-making power to the representatives.
(ii) Free and fair elections.
(iii) Universal adult franchise with each vote having equal value.
(iv) Fundamental rights and protection of individual freedom.

(i) The development of script marks the beginning of the historical period.
(ii) The period before the use, of written script is called prehistoric period.

(i) Polar Easterlies blow form the high pressure areas of the Polar highs at the North and South Poles towards low pressure areas within westerlies at high altitudes.
(ii) When air moves near the poles, cold temperatures shrink the air. So Polar Easterlies are cold and dry.

The atmospheric pressure is measured with a mercury barometer and the unit of measurement is millibar (mb).

(i) Hammurabi Code is an important legal document that specifies the laws related to various crimes.
(ii) It has 282 provisions specifying cases related to family rights, trade, slavery, taxes and wages.
(iii) It is carved on a stone, which portrays Hammurabi as receiving the code from the Sun god Shamash.
(iv) It was a compilation of old laws based on retributive principles.
(v) The 'eye for eye' and 'tooth for tooth' form of justice is used in the Hammurabi Code.

a)

b)

c)

(i) NNP - Net National Product
(ii) PCI - Per Capita Income

(i) The Harappan civilisation.
(ii) The Harappans used baked and unbaked bricks and stones for construction.
(iii) The Harappans used painted potteries. Their potteries have a deep red slip and black paintings.
(iv) The Indus people buried the dead. Burials were done elaborately.

The upper portion of the Thermosphere has uneven composition of gases and hence it is referred as "Heterosphere".