Questions: Question number 19 The nucleus is bound by a complex nuclear membrane, often called the . nuclear envelope sarcolemma plasma membrane neurolemma

The answer is the first one: nuclear envelope.

Explanation for each option:

1. Nuclear envelope: This is the correct answer. The nuclear envelope is a double membrane structure that surrounds the nucleus in eukaryotic cells, separating the contents of the nucleus from the cytoplasm and providing structural support.

2. Sarcolemma: This is incorrect. The sarcolemma is the cell membrane of a muscle cell, not related to the nucleus.

3. Plasma membrane: This is incorrect. The plasma membrane is the outer membrane of a cell, which encloses the cell's contents and regulates the movement of substances in and out of the cell, but it is not specific to the nucleus.

4. Neurolemma: This is incorrect. The neurolemma, also known as the Schwann cell sheath, is the outermost layer of the nerve fiber in the peripheral nervous system, not related to the nucleus.

In summary, the correct term for the complex nuclear membrane is the nuclear envelope.