B. Is the correct answer.
The important role of the atmosphere is to supply oxygen, water, carbon dioxide and nutrients. It also protects all living things from extreme temperatures and radiation (protects us from harmful solar rays).
Answer: The cell membrane is selectively permeable.
Explanation: going thru last year notes
Hydrochloric acid is a strong acid (fully dissociates when dissolved in water due to the polar covalent bond)
It is a very stable molecule
It is highly reactive with metals and with oxidising agents such as organic materials, alkalis, water etc.
Can be extremely corrosive if solution is concentrated.