See the multi-choice question below:

Sentence 1: This is an important assumption, because fine particles from power plant emissions are chemically different from directly emitted fine particles from both mobile sources and other industrial facilities, but no clear scientific grounds exist for supporting differential effects estimates by particle type.

Sentence 2: Not all emissions from industrial plants are the same.

If the first sentence is true, then is the second sentence true?
Select from:
+ yes;
+ it is not possible to tell;
+ no;
yes