What is the term for the dense, active protoplasm found in the center of the cell?

The correct term for the dense, active protoplasm found in the center of the cell is the nucleus. The nucleus is often referred to as the control center of the cell, as it houses the cell's genetic material (DNA) and is responsible for regulating various cellular activities, including growth, metabolism, and reproduction.

The nucleus is distinct because it is a membrane-bound structure that separates its contents from the rest of the cell, allowing for the organization and expression of genetic information. It plays a crucial role in processes like cell division and the synthesis of ribonucleic acid (RNA) for protein production.

In contrast to the nucleus, cytoplasm refers to the material within the cell membrane excluding the nucleus. The ribosome is a cellular structure that is involved in protein synthesis, while the cell membrane is the protective barrier that surrounds the entire cell. Each of these components has specific functions that are vital to maintaining cellular integrity and function.