The human body is organized at different levels, starting with the cell. Cells are organized into tissues, and tissues form organs. Organs are organized into organ systems such as the skeletal and muscular systems.
Evolution maybe?
Hope this helped
This solar energy conversion process is known as photosynthesis. ... At this time, the oxygen level was approximately 10% of its present atmospheric concentration. ... The presence of ozone enabled organisms to develop and live on the land.
