Biological assimilation, or bio-assimilation, is the combination of two processes to supply cells with nutrients. The first is the process of absorption of vitamins, minerals, and other chemicals from food within the gastrointestinal tract. The second process of bio assimilation is the chemical alteration of substances in the bloodstream by the liver or cellular secretions. Hence, assimilation is the process by which the absorbed food carried by the blood is used by the cells of the body for their activities.
So, the correct answer is 'The process by which the absorbed food carried by the blood is utilized by the cells of the body'.