Which of the following levels of organisation in living things is in the correct sequence, starting from the most complex to me simplest?

The correct sequence, starting from the most complex to the simplest level of organization in living things, is: System → Organ → Tissue → Cell. Explanation: A system is made up of different organs that work together to perform specific functions, such as the digestive system or the circulatory system. Organs are composed of different tissues that work together, for example, the heart is made up of muscle tissue, connective tissue, and nervous tissue. Tissues are made up of similar cells that work together to perform a specific function. Cells are the smallest unit of life, and they are the building blocks of tissues. Therefore, the correct sequence, starting from the most complex to the simplest level of organization, is System → Organ → Tissue → Cell.