Premise:
"Some participants believed that separation of the CEO and chairman of the board positions recognizes the differences in their roles and eliminates conflicts in functions."
Hypothesis: It is commonplace for the CEO to also serve as the chairman of the board.

it is not possible to tell

Premise:
"(Apparently, it was a happy arrangement for all.)"
Hypothesis: Everyone didn't like the arrangement.

no

Premise:
"They are said to be some of the finest prehistoric cave drawings ever discovered."
Hypothesis: These prehistoric cave drawings are said to be some of the finest ever discovered.
yes