Scientists are analyzing the movement patterns of slime mold, which

Hi neha283 santorasantu , this is a tough one. I'll try to attack this question from a couple angles. Hopefully one of them will suffice.

Meaning:
Let's read the sentence without the modifier that is surrounded by comma's.

"Scientists are analyzing the movement patterns of slime mold in an effort to better understand how to optimize traffic patterns."

Okay, so scientists are trying to improve their understanding of how to optimize traffic patterns. Cool. How do they plan on bettering their understanding? They're going to look at slime mold.

Why look at slime mold? Well, slime mold finds food by growing outwards. Once the mold finds some food, it then retracts from everything except the most efficient route to the food.

Let's check out some answer choices.


The mold grows outward by retracting? That's impossible. Is it growing outward or retracting? Meaning error.


This once is icky. We added another comma here, so we can't remove the whole modifier to have that nice and clean sentence that I wrote at the beginning of this post.

"which grows outward" is clearly modifying "slime mold." Cool. I'm good with that.

What is "searching for its food sources and retracting from everything but the most efficient route" modifying? Is it modifying "slime mold"? It is modifying "Scientists?"

Further, The slime mold grows outward and then retracts, but growing outward does not cause it to retract.


This one doesn't sound good to me either, but who cares? GMAC sure doesn't. It doesn't sound good because of the verb forms "searches for X by growing outward and retracts from Y." If we remove that Prepositional phrase: "for its food sources by growing outward," then it will sound a lot better.

We're looking great from a parallelism point of view. "searches for X and retracts from Y"

This works great from a meaning perspective because it shows that the slime mold searches by growing outward and retracts from everything except the best route. These are two independent actions. They do not grow outward and retract at the same time.


I hope this helps someone.