All living organisms are made up of one or more cells, which are considered the fundamental units of life. Even unicellular organisms are complex! Inside each cell, atoms make up molecules, which make up cell organelles and structures. In multicellular organisms, similar cells form tissues.
<span>The area of the square is d^2. The area of the circle sandbox is πr^2=πd^2/4. So the area of play area only is equal to square area minus circle area which is d^2-πd^2/4.</span>
