Biology · Biotechnology and Cell Culture

In standard or batch cultures, cells are grown in a fixed volume of medium. As they grow, nutrients are consumed and metabolites accumulate. The following procedures may prolong the life of batch cultures: A. Gradual addition of fresh medium and increasing volume of the culture B. Replacing a constant fraction with an equal volume of fresh medium C. Occasional removal of used medium and reducing growth factors in the medium D. Intermittently adding serum and growth factors to the medium Which one of the following combinations will ensure healthy growth of cells in culture?