If you don’t know the answer to a short answer question, a guess made with common sense is likely to earn you more points than leaving the answer blank.
true or false

True, because yes at least you would get more credit then a 0

It depends on the question. If the question is philosophical, than you will most likely receive no points either way. If it is a common sense question than you will most likely receive partial or full points instead of no points at all.