Which of the Following Lists the Levels of Biological Organization

Which of the following lists the levels of biological organization in order from simplest to most complex?

A) cell, cardiac muscle, heart, cardiovascular system, human
B) cardiac muscle, cell, human, heart, cardiovascular system
C) human, heart, cardiovascular system, cardiac muscle, cell
D) cell, heart, human, cardiovascular system, cardiac muscle
E) heart, human, cell, cardiac muscle, cardiovascular system The simplest level of organization of living things is the cell. Tissues are composed of cells, organs are composed of tissues, and organ systems are composed of organs.