Please make sure not to paste answer while posting questions.

The Jock wrote:Although ice particles in the upper atmosphere benefit Earth in that they reflect and absorb solar radiation, acting as a global thermostat and thus keeping Earth from either burning up or freezing over, thev also accelerate the destruction of the ozone layer by reacting with chlorofluorocarbons (CFC's).
A. acting as a global thermostat and thus keeping Earth from either burning up or freezing over, they also accelerate
Correct
B. acting as a global thermostat and thus keeping Earth either from burning up or freezing over, while also accelerating
C. act as a global thermostat and thus keep Earth from either burning up or freezing over, while also accelerating
D. they act as a global thermostat that thus keeps Earth either from burning up or freezing over, even though it also accelerates
E. they act as a global thermostat to thus keep Earth from either burning up or freezing over, but they also accelerate

This is a GMAT Prep question.
I got confused between A and C.

Post edited...
Thanks for pointing out...it was a copy-paste mistake...

I went with my ear in this question. How to approach it grammatically?

The Jock wrote:Although ice particles in the upper atmosphere benefit Earth in that they reflect and absorb solar radiation, acting as a global thermostat and thus keeping Earth from either burning up or freezing over, thev also accelerate the destruction of the ozone layer by reacting with chlorofluorocarbons (CFC's).
A. acting as a global thermostat and thus keeping Earth from either burning up or freezing over, they also accelerate
B. acting as a global thermostat and thus keeping Earth either from burning up or freezing over, while also accelerating
C. act as a global thermostat and thus keep Earth from either burning up or freezing over, while also accelerating
D. they act as a global thermostat that thus keeps Earth either from burning up or freezing over, even though it also accelerates
E. they act as a global thermostat to thus keep Earth from either burning up or freezing over, but they also accelerate

This is a GMAT Prep question.
I got confused between A and C.

IMO A

In C, "while also accelerating" creates a sentence fragment. it does not complete the sentence

Read it like this

Although A is responsible for X, he also does y

Although A is responsible for X, while also doing Y

Which answer choice seems correct?

Also while has 2 different meanings...

The Jock wrote:Although ice particles in the upper atmosphere benefit Earth in that they reflect and absorb solar radiation, acting as a global thermostat and thus keeping Earth from either burning up or freezing over, thev also accelerate the destruction of the ozone layer by reacting with chlorofluorocarbons (CFC's).
A. acting as a global thermostat and thus keeping Earth from either burning up or freezing over, they also accelerate
B. acting as a global thermostat and thus keeping Earth either from burning up or freezing over, while also accelerating
C. act as a global thermostat and thus keep Earth from either burning up or freezing over, while also accelerating
D. they act as a global thermostat that thus keeps Earth either from burning up or freezing over, even though it also accelerates
E. they act as a global thermostat to thus keep Earth from either burning up or freezing over, but they also accelerate

This is a GMAT Prep question.
I got confused between A and C.

I vote for E because Although and but are properly matched over there.

Please correct.

Regards,

Pranay

Answer should be A.

B violates " either x or y "
C misuses while.

I came to the choice A by POE

in A acting is modifying "ice particles" or "ice particles in the upper atmosphere benefit Earth in that they reflect and absorb solar radiation" ?

I think it should be A.

Here is my explaination:

- D can easily be ruled out becasues it uses "keeps" - Read the simple statement as 'Particles keeps earth burning up' vs 'Particle keep earth burning up'.
Also as correctly pointed out in previous post, construction

Although X , eve though y doesn't look right

- E can be ruled out for same reason.

Although X ,but Y doesn't look right

- B and C can be ruled out or same reason again

Although X while also Y doesn't look right

- A is the correct answer : On the first glance it looks like an issue with parallelism but its not.

Here, consider this

X = Although ice particles in the upper atmosphere benefit Earth in that they reflect and absorb solar radiation, acting as a global thermostat and thus keeping Earth from either burning up or freezing over,

So, ice particles benefit earth in that they reflect and absorb solar radiation
The next part of X explains HOW ice particles do that, so its not necessary to use parallelism here.

IMO A.
Please correct me if I am wrong but, the present participle should be used, in case of this sentence 'acting' to indicate all are happening in the same time frame. ' acting as a global thermostat '

Options CDE can be eliminated.

Although ice particles in the upper atmosphere benefit Earth in that they reflect and absorb solar radiation, acting as a global thermostat and thus keeping Earth from either burning up or freezing over, thev also accelerate the destruction of the ozone layer by reacting with chlorofluorocarbons (CFC's).

A. [acting] as a global thermostat and thus [keeping] Earth from either (burning) up or (freezing) over, they also accelerate
B. [acting] as a global thermostat and thus [keeping] Earth either (from burning) up or (freezing over), while also accelerating
C. act as a global thermostat and thus keep Earth from either (burning) up or (freezing) over, {while also} accelerating
D. they act as a global thermostat that thus keeps Earth either (from burning) up or (freezing) over, {even though} it also accelerates
E. they act as a global thermostat to thus keep Earth from either (burning) up or (freezing) over, {but} they also accelerate

Answer is A