Psychologists suggest that to cure cruelty

The author of the passage points out that

1. 
   the consumption of pork products is not very safe for health concerns
   
2. 
   though dirty, the pig is not too filthy to be touched
   
3. 
   pigs supply humans with very many types of products
   
4. 
   although the meat is unsafe, pigs can be a source of leather and brushes
   

2. 
   When pigs are provided with the right conditions,
   

1. 
   the quality of the pork meat is improved
   
2. 
   pigs are still extremely dirty
   
3. 
   pigs like to keep themselves clean
   
4. 
   bristles obtained from them for brushes are of better quality