Does active transport requires a semi-permeable membrane ?Recently I came to a question in my mid-year examination and my head went all blank when...

Active transport is from higher to lower concentration
gradient. It is a law of nature that in this case energy will be required. So I think
option "A" is correct.

Carrier proteins are some proteins
(like fibers) which grab the material and transport it. This phenomenon occurs in
diffusion, osmosis as well as active transport but not always. I mean that it is not a
hard and fast rule that they will always be required for active
transport.

Active transport does not folow concentration
gradient i.e form higher to lower. In fact ti is the exact
opposite.

When a membrane comes in between the process is
known as osmosis. Active transport does not require a membrane.