how to guess the conclusion of a passage?

[raksmba]

The hard, rigid plates that form the outermost portion of the Earth are about 100

kilometers thick. These plates include both the Earth's crust and the upper mantle.

The rocks of the crust are composed mostly of minerals with light elements, like

aluminum and sodium, while the mantle contains some heavier elements, like iron and

magnesium. Together, the crust and upper mantle that form the surface plates are called

the lithosphere. This rigid layer floats on the denser material of the lower mantle the way

a wooden raft floats on a pond. The plates are supported by a weak, plastic layer of the

lower mantle called the asthenosphere. Also like a raft on a pond, the lithospheric plates

are carried along by slow currents in this more fluid layer beneath them.

With an understanding of plate tectonics, geologists have put together a new history

for the Earth's surface. About 200 million years ago, the plates at the Earth's surface

formed a "supercontinent" called Pangaea. When this super continent started to tear

apart because of plate movement, Pangaea first broke into two large continental masses

with a newly formed sea that grew between the land areas as the depression filled with

water. The southern one — which included the modern continents of South America,

Africa, Australia, and Antarctica — is called Gondwanaland. The northern one — with

North America, Europe, and Asia — is called Laurasia. North America tore away from

Europe about 180 million years ago, forming the northern Atlantic Ocean.

Some of the lithospheric plates carry ocean floor and others carry land masses or a

combination of the two types. The movement of the lithospheric plates is responsible for

earthquakes, volcanoes, and the Earth's largest mountain ranges. Current understanding

of the interaction between different plates explains why these occur where they do. For

example, the edge of the Pacific Ocean has been called the "Ring of Fire" because so

many volcanic eruptions and, earthquakes happen there. Before the 1960' s, geologists

could not explain why active volcanoes and strong earthquakes were concentrated in that

region. The theory of plate tectonics gave them an answer.

 

The paragraph following the passage

most probably discusses

(A) why certain geological events happen

where they do

(B) how geological occurrences have

changed over the years

© the most unusual geological

developments in the Earth's history

(D) the latest innovations in geological

measurement

 

answer :A

[kutti]

hi raksmba,

I am new to this forum.

I seen your post today.

 

My idea for u is "go through the very first line of each paragraph"

 

It will help u to get the idea "what the passage actually mean"

 

ans is A