Answer:
Letter B.
Explanation:
Aquaporins, also known as "water channels," are the main transport of water through the membranes of plant, animal, and bacterial cells. These channels allow the water to travel into and within cells and, at the same time, exclude the passage of ions and solutes.
What makes letter B the correct answer, is the form of transport and shape of the channel that allow water according to the osmotic gradient. In this model, letter A shows simple diffusion, while C and D seem to illustrate gated channels.
 
        
             
        
        
        
Properties of metals are traits displayed by most metals.
        
             
        
        
        
Scientists classify living things to organize and make sense of the incredible diversity of life. Classification also helps us understand how living things are related to each other.
        
             
        
        
        
Answer:
cell membrane is the outer boundary present around the cells functions to protect the inner cellular material from outer invaders and maintain the shape of cell
Explanation:
Cell membrane is the outer most boundary made up of lipids and proteins.
Mainly the membrane is composed of lipid bilayer in which protein chains are embedded