Answer:
three types of stimuli—mechanical, thermal, and chemical; some endings respond primarily to one type of stimulation, whereas other endings can detect all types. Chemical substances produced by the body that excite pain receptors include bradykinin, serotonin, and histamine."
Explanation:
From edge
 
        
             
        
        
        
<span>In sanitary landfills, liquid that is produced by the interaction of rainwater with solid waste is called a leachate. This is because when rainwater makes contact with the solid wastes which are usually buried, the liquid draws out chemical constituents from those wastes. The leachate can then carry harmful substances that can seep through underground and affect groundwater.</span>
        
                    
             
        
        
        
Answer:
Background extinction
Explanation:
The background extinction refers to the diminishing of the species at a fairly slow and constant rate. This extinction takes place because of the various environmental factors namely the changing climatic conditions, spreading of diseases, and destruction of habitat. It plays an important role in the natural process of evolution. This has been taking place continuously throughout the geological time and the species are undergoing continuous evolution over a specific period of time.
 
        
             
        
        
        
The basic unit of a chemical element.