A learner makes a note: an octopus releases a dark cloud that distracts predators during escape. The missing scientific idea is:

Many cephalopods possess an ink sac that releases ink as a defensive mechanism. It can confuse predators while the animal escapes by jet propulsion or hiding. This MCQ belongs to the Cephalopoda topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.