Question

how many membranes are there and what are they called?
2 membranes the singular membrane and dual membrane
2 membranes called inner membrane and outer membrane.
2 membranes called external membrane and internal membrane.
1 membrane called the bilipid membrane

Explanation:

In many cellular - organelles like mitochondria and chloroplasts, there are two membranes known as the inner membrane and the outer membrane. This is a well - known concept in cell biology.

Answer:

B. 2 membranes called inner membrane and outer membrane.