Task 3 Complete the sentences with: involuntary, endorphins, hormones, cells and epinephrine. 11 When we exercise our bodies release a chemical that helps concentration. that we 12 Our memory and creativity depend on the number of brain have. 13 The in our body are feel good chemicals that make us feel relaxed and happy. 14 The growth and strength of our muscles can be affected by our muscles because they 15 Some muscles in our bodies are called function automatically