Earth's surface consists of rigid plates that are

Agree with the first three.

why it's E not A for the last question?

Established plume means it's not "untapped" any more, I think.

DBEE

For the 3rd, nothing in the passage suggests that the track of the plume was used to identify that the plates actually moved.

I thought that the second question with its reference to 'over a period of time' and then 'age' in the correct answer choice was a bit trickier than the rest.

Hello, the OA is D,B,E,E

In the second question, why not A?

How to infer ?

could anybody tell me, please.

chunjuwu,
I am by no means an authority is RC, but here is my 2 cents.
only reference to Hawaiian islands we have in the passage is
"The natural history of the Hawaiian island chain clearly shows the movement of the Pacific plate over a fixed plume".

in other words, the Author is using Hawaiian islands to explain a particular phenomenon. No where he mentions that this type of activity doesn't occur else where in the world. Hence choice A is wrong

Hope this helps

chunjuwu I got your message, here is what I feel about Q 23

Q23 states
It can be inferred from the passage that a chain of volcanoes created by a mantle plume would most likely be characterized by

A. a curved outline
B. constituent volcanoes that differ from each other in age


A is indeed very tempting. But it is out of context. Passage says

"Because the source of a hot spot remains fixed while a surface plate moves over it, over a long period of time an active plume creates a chain of volcanoes or volcanic islands, a track marking the position of the plume relative to the moving plate."
earlier in the passage it also states

"When the edge of one plate bends under another and its cooler material is consumed in the mantle, volcanic activity occurs as molten lava rises from the downgoing plate and erupts through the overlying one."


that means here emphasis is on the fact that hot spot remains fixed and plates move over it. When the hot spot hits the edges of the plates lava comes out. That means there is a time gap in between volcanos. Hence choice B

Even though the passage states "a track marking the position of the plume relative to the moving plate" it doesn't necessarily mean it is a curved outline because we don't really know how the plates move.

I think the first questions answer is D

Second one is B

Thirs is E

Fourth is E too

Man this was a tough one...took me 15 minutes to figure out

Whts the OA

A is irrelevant
You know that it's B because of this part "the source of a hot spot remains fixed while a surface plate moves over it, over a long period of time an active plume creates a chain of volcanoes "