The plasma membrane: Question 3 options: is the gene-containing control center that directs all cellular activities regulates the entry and exit of cell materials is the site where ribosomes are assembled prior to their migration into the cytoplasm defines the limits of the nucleus

The plasma membrane (regulates the entry and exit of cell materials).

Explanation:

All living organisms are composed of one or more cells. The cell can be defined as the smallest functional unit of all living organisms. Also called the basic organizational unit of life.

Cells are found to have many features in common. However, a generalized cell does not exist. The precise structure of a cell is closely related to the work it does.

According to the structure of a cell, it has a living material called protoplasm. The protoplasm is enclosed by a membrane known as the PLASMA MEMBRANE.

The PLASMA MEMBRANE is a flexible membrane that is made up of mainly proteins and lipids. It prevents the cell contents from escaping to the exterior. It is also selectively permeable, that is, it controls the materials which are allowed to enter or leave the cell.

Other structures of a cell include:

--> Nucleus: This is the most important cell structure as it houses the genetic information of the cell.

--> The cell wall: this surrounds the plasma membrane but is freely permeable.