(Why were the grizzlies starting to catch fewer fish?)
Cause: The salmon run slowed down
Effect: The bears of the Brooks River caught fewer and fewer fish. (p.18)
Fact/opinion
Is the following statement about The Grizzly Bear with the Golden Ears a fact or an opinion?
"Golden Ears was no longer inclined to return to the Brooks River once she was reunited with her cub."
(This statement is a fact.)