Explanation

Explanation

Natural graphite is used in many ways, from making pencils lead, to forming batteries.

The layered structure formed due to rings of carbon atoms present in Graphite makes it slippery and for that reason, it is used in Pencil leads.

Graphite was named by Abraham Gottlob Werner in 1789.

It is an allotrope of carbon.

Graphite is a good conductor of electricity.

Explanation

• Coal, fossil fuels, crude oil, natural gas, etc are all hydrocarbon fuels.
• These are called as non-renewable source of energy because they take millions of years to regenerate themselves.
• Water energy is renewable because it is regenerated by water cycle.
• Also wind energy and solar energy are renewable sources of energy.

Explanation

The air in Earth's atmosphere is made up of approximately 78 percent nitrogen and 21 percent oxygen.

Explanation

A seismograph is an instrument used to detect and record earthquakes.

It consists of a mass attached to a fixed base

During an earthquake, the base moves and the mass does not.

Explanation

Explanation

Singular noun: Leave 

Plural noun: Leaves 

Leave means پتہ

Explanation

Hydroelectric power is considered the cheapest and most environmentally friendly source of electricity.

As it utilizes the energy from flowing water without emitting greenhouse gases.

Explanation

Karl Landsteiner discovered ABO blood group system.

He was an Austrian scientist.

Karl Landsteiner received Noble Prize in 1930

Blood Group System was discovered in 1900.

Explanation

AB positive (AB+)

and O negative (O-) are considered universal blood types

because they can receive blood from all blood kinds

without experiencing any hemolytic reactions.