2. Cardiac muscles are very strong, because they have no rest 3. Humans have only 3 types of muscles According to the story complete these sentences. 1. Skeletal muscles are also called A) Movement muscles B) voluntary muscles C) smooth muscles 2. Cardiac muscles are only in the walls of A) the brain B) the lungs C) the heart. 3. Smiling require several muscle groups to work A) Alone B) Together C) One by one​