An avocado can be a simple model of the structure of a cell.
Which cell structure is represented by the avocado's skin?

the cell membrane

Explanation:

it :

protects the cell by acting as a barrier.regulates the transport of substances in and out of the cell.receives chemical messengers from other cell.acts as a receptor.cell mobility, secretions, and absorptions of substances.

According to arrhenius theory of acid and bases, an acid is a proton donor, while base donates hydroxyl ions. further, acid and base reacts to form salt and water.consider following example.hcl    +      h2o          →      cl-          +      h3o+here, hcl has donated a proton, hence it is an acid.now consider following reactionhcl      +      naoh            ↔      nacl      +        h2oin this reaction, hcl donates proton, hence it is acid. on other hand, naoh donates hydroxyl ion (i.e. hence it is a base.