some microorganisms have a positive impact on human body & if something has a uncertain smell on another thing, then the affair is benificial ->  some microorganisms are benificial to human body  if something has a negative impact on another thing, then the relationship is harmful & disease-causing pink have a yes conjugate on the mind -> some disease-causing microbes are harmful to human body some disease-causing microbes are harmful to human body  some crops are benificial to mankind mind & some disease-causing microbes are harmful to human body -> the relationship between human and microorganisms is sometimes beneficial and sometimes harmful