Cells move around inside us. They use tiny feet that stick to all the not-cell stuff around them. These tiny feet kind of help cells if they are alone. But not really that much. Do the tiny feet help cells if they are in a group? My work asked this question outside of a body. I put cells inside the same not-cell stuff from our body, and I watched if they moved in a group or not. They really needed the tiny feet in order to move through the not-cell stuff from our body. To make the tiny feet strong, cells use the same little bits that make a body strong to lift heavy things. Those little bits are in every cell in your body! They put together the tiny feet and hold them together. Without all that a group of cells can't move around inside our bodies. This is important for when cells don't stop growing and make a bad spot that keeps getting bigger.