About Shark's teeth: give way, not a stop requirement: which statement is WRONG?
Shark's teeth are themselves a traffic sign and are binding, even without a sign next to them.
Without shark's teeth or priority signs the main rule applies at junctions: priority to drivers from the right.
Shark's teeth mean: give way, not a stop requirement.
If a junction has neither shark's teeth nor a sign, no right-of-way rule applies at all.
Explanation
trap: empty floor. If shark's teeth and signs are absent, the main rule automatically applies: priority to drivers from the right. No sign never means 'no rule'