Wrong! All of you! On some of them.
1) There are negative grades, and assuming the teacher takes off 5 points for every wrong word starting at 0, the lowest possible grade for the student was a 100.
2) When the moon first formed. A moon landing could mean any piece of debris landing on its surface; the exact period of this happening depends on why you think the moon formed.
3) It's a photgraphic negative (colors inverted).
4) They are pro open source (double letters was not the pattern; "Penguin" has two n's and is favored, while "Apple" has two P's and is disliked. Also note that alligator was taken out because what I mistook for an alligator was in fact a dragon).
5) There was a warrant for his arrest; the fact he does anything in a candy store is highly suspect and hints at prior sinister acts, but has nothing to do with the solution.
6) Organise a jailbreak while using the dental floss for hand gestures (or, if you want a solution which doesn't leave you feeling like a complete rube, sneak up on a guard, choke him with it, take his weapons and keys, and stealthily leave the area).
As for these being riddles and not cryptograms, I quote:
You probably know cryptograms by another name-logic puzzles. However, by saying "logic puzzle", you're admitting just how trivial what you're doing is, so the term cryptogram is sometimes used instead (or maybe it means something entirely different; it's a possibility).
And I'm not changing the topic title either.
Thought of write now (really):
1) What is East South of?
2) Three sticks are on a table, and cut in such a way where six sticks of the same size remain. How?
3) If the red curtain is blue and the blue curtain is red, does this mean you can recognise basic patterns?
4) A battery is put in a microwave for an hour on the highest power, but doesn't explode. Why?
5) As the temperature increased, some water froze. How?
6) 6Sg=5??, and 9Nj=3Td are identical based only on operation. What goes in the '??'?
And so on to infinitum.