Question

which structure gives the cell a boundary?
cell membrane
mesoderm
nuclear envelope

Explanation:

The cell membrane is a semi - permeable barrier that surrounds the cell, separating the interior of the cell from the external environment. The mesoderm is one of the three primary germ layers in an embryo and not a cell - boundary structure. The nuclear envelope surrounds the nucleus within the cell, not the entire cell.

Answer:

cell membrane