Solution:
Given:
Fact 1 - If a whale has exactly one nostril (also called a blowhole), then that whale has teeth.
Fact 2 - some whales have two nostrils.
From the above statements;
If a whale has teeth, then that whale has exactly one nostril. This is NOT TRUE because there are some whales that have two nostrils.
If a whale has two nostrils, then that whale has teeth. This is also NOT TRUE because there are some whales that have one nostril and have teeth.
If a whale has teeth, then that whale has two nostrils. This is NOT TRUE because if a whale has exactly one nostril, then that whale has teeth.
Therefore, none of the preceding three conclusions follows logically from the two given facts.