Yes / no, is the following a verifiable fact?
"Zebra eat grass that is green and short, but in a pinch they'll eat all kinds of grass."

Let me think out loud. The sentence is true because animal experts and people that closely study the diets of zebras have said that grass is what zebras prefer to eat. The answer is yes.

Is the following statement true?
"The Red Army defended itself from Hitler's troops as they invaded in WWII."

Let me think out loud. Weather and the persistence of the Russians were able to keep the Nazi's from invading Russia. The answer is yes.

Is the following statement true?
"Frost precipitation occurs when the temperature of the surface falls below the Frost point."
Let me think out loud. Frost forms when an outside surface cools past the frost point. The answer is yes.