Answer:
plz attach answer choices, i will revise my answer
Explanation:
 
        
             
        
        
        
Ans. 
Cell-to-cell communication allows signalling of essential substances between the plant cells, which are surrounded by cell walls. The molecules used by plants for long-distance signalling are known as hormones, such as auxin, ethylene, and gibberelin. 
These hormones are secreted by one plant cell and received by another plant cell, where it exerts it affect. Thus, the correct answer to be fill in the blank is 'option A). hormones.'
 
        
             
        
        
        
Answer:
Rough endoplasmic reticulum differ from smooth endoplasmic reticulum by the presence and absence of ribosomes in their surface.
Explanation:
Rough endoplasmic is named so because RER contain ribosomes at their surface and due to the presence of ribosomes rough endoplasmic reticulum play an importnt role in protein synthesis or translation.
  Whereas smooth endoplasmic reticulum does not contain any ribosome in its surface.smooth endoplasmic reticulum helps in the biosynthesis of lipid and steroids along with detoxification of toxic compounds.
 
        
             
        
        
        
<span>By filtering the air so that the lungs so the lungs don't get infected</span>