The term 'make a mussle' can be solved by the crossword solution STEAM, which is an acronym for Science, Technology, Engineering, Arts, and Mathematics. This term is used to describe the five core disciplines of learning that are essential for success in the 21st century. STEAM education encourages students to think critically and creatively, and to develop problem-solving skills. It also helps students to become more engaged in their learning and to develop a deeper understanding of the world around them.