The answer would be A.
The question you have to ask is, is it possessive?
Yes it is possessive.
The wing is owned by the bird. Its wing was broken.
It's means it is or it has.
It's would not make sense in this case because you can not put it is or it has into this sentence.
Answer:
A. They also help the environment by refreshing the air and by reducing smog and effects to the ozone layer.
Explanation:
The author makes a claim that environment is refreshing by the air and the effects on ozone layer are reduced. This statement is not supported by the evidence. The ozone layer is polluted by the environment pollution. The pollution created by humans is also affecting the air which ultimately pollutes the ozone layer.
in Joy Harjo's "New Orleans", the line "beaten silver paths" refers to the streets of such city. She remembers of certain Spanish conqueror, De Soto,who came to this lands searching for, and constantly states that he wouldn't find it here. Maybe is a mock to that fact.
The "silver blades and crosses" refers to the sword and crucifix of the conqueror, who drawn in the Mississippi river which dreamt of those items. Maybe this means that the streets of New Orleans were made of the things and dreams of the many conquerors who came to that land in search for gold and failed.
It’s b Blanche that’s enough sewing