Last chance for SAT on Oct. 6th><
Waiting for help!
Pictures of vipers drawn on the walls of caves suggest that prehistoric hunters may have used snakes charms [for bringing] good luck.
The  part is the right choice, but I looked up in my Longman dictionary and it says that there is the phrase "use sth for (doing) sth". Is it that the phrase is wrong in SAT?
Captive-bred whooping cranes have no parents to teach them migratory habits, [this fact explaining why they] must be led on their first migration by humans flying microlight aircraft.
Is the sentence correct if "this fact" is deleted?
A thick growth of sunflowers [standing ten feet tall, their brown heads drooped] over the fense with the weight of their seeds.
The correct answer is [stood ten feet tall, their brown heads drooping]
I can't see any difference in grammatical structure..
Intimacy, love, and marriage are three [different, if interrelated, subjects].
the correct answer is A, but I chose C[different subjects, whereas they are interrelated]
Why C is wrong?
I googled the question and one explanation is that the "if" in the original sentence means "even if". Is this explanation correct?
London [differs from] other cities, such as Paris and New York, [in that] its shopping areas are so [widely] spread out.
The right choice is E, no error.
I thought that "widely" is used to describe some abstract verbs and "wide" to some concrete verbs. Why it shouldn't be "wide" ( "extending over a vast area") here?