Anthracite is usually considered to be the highest grade of coal and is actually considered to be metamorphic. Compared to other coals it is much harder, has a glassy luster, and is denser and blacker with few impurities. It is largely used for heating domestically as it burns with little smoke.

Correct Option: D

Anthracite is usually considered to be the highest grade of coal and is actually considered to be metamorphic. Compared to other coals it is much harder, has a glassy luster, and is denser and blacker with few impurities. It is largely used for heating domestically as it burns with little smoke.

Most earthquakes are minor tremors. Larger earthquakes usually begin with slight tremors but rapidly take the form of one or more violent shocks, and end in vibrations of gradually diminishing force called aftershocks. The subterranean point of origin of an earthquake is called its focus; the point on the surface directly above the focus is the epicenter.

Correct Option: A

Most earthquakes are minor tremors. Larger earthquakes usually begin with slight tremors but rapidly take the form of one or more violent shocks, and end in vibrations of gradually diminishing force called aftershocks. The subterranean point of origin of an earthquake is called its focus; the point on the surface directly above the focus is the epicenter.

The International Date Line (IDL) is an imaginary line on the surface of the Earth, that runs from the north to the south pole and demarcates one calendar day from the next. It passes through the middle of the Pacific Ocean, roughly following the 180° longitude but it deviates to pass around some territories and island groups.

Correct Option: D

The International Date Line (IDL) is an imaginary line on the surface of the Earth, that runs from the north to the south pole and demarcates one calendar day from the next. It passes through the middle of the Pacific Ocean, roughly following the 180° longitude but it deviates to pass around some territories and island groups.

A method is described whereby, using primitive equipment anyone can measure the size of the earth to an accuracy of order of magnitude 10% by observing two sunsets in the space of a few seconds.

Correct Option: C

A method is described whereby, using primitive equipment anyone can measure the size of the earth to an accuracy of order of magnitude 10% by observing two sunsets in the space of a few seconds.

The Mohorovicic discontinuity, usually referred to as the Moho, is the boundary between the Earth’s crust and the mantle. Named after the pioneering Croatian seismologist Andrija Mohorovicic, the Moho separates both the oceanic crust and continental crust from underlying mantle. The Moho mostly lies entirely within the lithosphere; only beneath mid-ocean ridges does it define the lithosphere – asthenosphere boundary..

Correct Option: D

The Mohorovicic discontinuity, usually referred to as the Moho, is the boundary between the Earth’s crust and the mantle. Named after the pioneering Croatian seismologist Andrija Mohorovicic, the Moho separates both the oceanic crust and continental crust from underlying mantle. The Moho mostly lies entirely within the lithosphere; only beneath mid-ocean ridges does it define the lithosphere – asthenosphere boundary..