An object pronoun takes the place of a/an in the object part of a sentence. 

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.

1. b

2. a deadly disease

4. at the same time

5. a) true

b) true

c)false?

d)false?

7. para.1 = c

para.2 = d

para.3 = f

para.4= b

para.5= e

para.6 = a