positive feedback could be contractions(as painful as it may seem, its true) in child birth and the ripening of fruit.
negative feedback include the regulation of blood glucose levels and osmoregulation
The weathering process occurs when rocks are exposed to the hydrosphere (water) and atmosphere (air).
Once the DNA of a person has been copied it can be compared to the DNA of other people by using PCR (Polymerase Chain Reaction).
