Question

the nuclear envelope differs from the cell membrane and the membranous endoplasmic reticulum because it:

• does not contain proteins.
• is a double membrane.
• is not permeable.
• is very rigid.

Explanation:

The nuclear envelope is distinct from the cell membrane (single membrane) and endoplasmic reticulum (single membrane) because it consists of two lipid bilayers (a double membrane). All these structures contain proteins; the nuclear envelope is permeable via nuclear pores; and it is not very rigid compared to structures like the cell wall. Thus, the key difference is being a double membrane.

Answer:

B. is a double membrane.