What features characterize an organism as a habitat for parasites?

1) unlimited supply of easily digestible food
2) protection (from external factors, from drying out, from enemies)
3) constancy of salt composition and osmotic pressure

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.