What is feynman’s technic in studies ! ?

"The Feynman Technique is a mental model that was coined by Nobel-prize winning physicist Richard Feynman. Known as the "Great Explainer," Feynman was revered for his ability to clearly illustrate dense topics like quantum physics for virtually anybody."

answer; i believe the correct answer is ( proteins );

i think it would be b. tissue because an organ system is a group of organs that work together to perform one or more functions. each does a particular job in the body, and is made up of certain tissues.