Acomma is used to

form a contraction
connect two clauses with a conjunction
connect two independent clauses without a conjunction
create a plural possessive

Connect two independent clauses with a conjunction.

or

Connect two clauses with a conjunction.

the correct answer is c. he speculates on what might happen at given points in the future in a world without people. alan h. weisman is an american author, professor, and journalist. authors organize their information with a purpose. they present their ideas in an organized way. this is called text structure. weisman uses text structure so as to improve overall comprehension and to prove his points.

quarted means to be housed or "lodged" in someone home

hope this