Carbon dioxide is not safe for your lungs because once it reaches your lungs it will stop your breathing and you could die.
Explanation:
The cell membrane, therefore, has two functions: first, to be a barrier keeping the constituents of the cell in and unwanted substances out and, second, to be a gate allowing transport into the cell of essential nutrients and movement from the cell of waste products.
A vertebrate is an animal with a backbone.
Option D would be that answer
