Answer:
The answer is hormones.
Explanation:
Two of the main systems that control almost every action in our body are our nervous system and endocrine system which have to have inner communications and communication with our brain.
As stated in the question, nervous system uses neurotransmitters for communication which are chemicals released by neurons to generate electrical signals that make the communication possible.
The main mean of communication that our endocrine system uses is substances that are called "Hormones" which are produced by certain glands and organs in our body and are usually released into our bloodstream to effect the functions of other organs and our body. Hormones can be used for both communication of the endocrine system itself and for the communication of other organs and our brain.
I hope this answer helps.
 
        
             
        
        
        
Answer: cell membrane 
such as water, micro-organism
 physical process 
simple diffusion, osmosis and filtration 
such as potasssium permaganate in water,urea a liver waste diffuses from the body and the kidney help in filtering it out
physiological processs 
active transport, phagocytosis and pinocytosis
such as soduim-potassium pump, exocytosis
Explanation:  transportation in and out of cell is done in different ways listed above but a barrier to this movement is the cell membrane which is an outer covering of the cell. it protect the cell and only some materials can penetrate the cell membrane e.g micro-organism, water e.t.c. the various physical and physiological processes are the various ways substance  cna be liquid, solid or gas are transported within or outside the  cell e.g food
 
        
             
        
        
        
Are you talking about a fruit fly?