Aplastar una caso es un cambio químico o físico

Físico porque lo estás haciendo tú mismo, lo que lo hace físico. Si fuera químico, tendría que quemar la lata para que sea físico.  :]

Explanation:

the major pests we deal with are insects, weeds and fungal diseases. a pesticide is a product, whether organic or chemical, used to kill the target pest. there are other techniques gardeners should use that can prevent the severe infestations that make the use of pesticides necessary

b. accuracy of the data matters alot more than its number of digits, organization or amount of detail. quantitative observation is more accepted than the qualitative observation.