Today scientists can study human cells grown in petri dishes. Explain how this tenchnique builds on the work of early scientists

Early scientists were only able to study dead human cells in petri dishes. They could not keep cells alive in the lab. Now that scientists can keep cells alive using cell cultures, they can study the living processes of cells. Because of their advanced techniques in growing tissue cells, scientists are able to grow human brain tissue in 3D. This is one of the latest developments. Scientists have been able to grow human tissue cells in 2D for a while now.