What is the primary function of cytoplasm in a cell?

The primary function of cytoplasm is to serve as a medium for biochemical reactions. Cytoplasm is the gel-like substance that fills the interior of the cell, surrounding the organelles. It contains various enzymes, ions, and molecules that facilitate metabolic processes necessary for the cell's survival and function. Within the cytoplasm, numerous biochemical reactions occur, such as glycolysis and protein synthesis, which are crucial for energy production and cellular repair, among other processes.

In contrast, the other options describe different functions that are not characteristic of cytoplasm. For instance, a rigid structure for the cell is primarily provided by the cell wall in plants or by the cytoskeleton in all eukaryotic cells. The transport of nutrients across the membrane usually involves specific transport proteins or mechanisms like active transport and diffusion, which occur at the cell membrane rather than within the cytoplasm itself. Storing genetic information is the role of the nucleus, and while some organelles, like plastids in plants, may have genetic material, this is not a function assigned to cytoplasm. Thus, emphasizing that the cytoplasm's essential role is in facilitating biochemical reactions clarifies its importance in cellular function.