One of the primary advantages of cell culture is the ability to isolate a single type of cell from a multicellular organism.

One of the primary advantages of cell culture is the ability to isolate a single type of cell from a multicellular organism. How has this advance changed the study of biology?
Single-type cultures are easier and cheaper to maintain than cultures made of mixed cell types.
Scientists can completely avoid using animal or human test subjects during their experiments.
Cultures with single cell types behave in culture exactly as they would behave in a tissue or organ.
Scientists know that any response during an experiment is associated only with that cell type.