Question

question 18
an example of a positive feedback loop _______.
are birds migrating south in response to colder temperatures
is a thermostat turning on the furnace as the temperature drops
is a pond becoming more acidic as a result of pollution
are predators eating most of their prey and then declining in numbers
is melting arctic snow exposing dark surfaces that heat up and cause further melting

Explanation:

Positive - feedback loops amplify a change. Melting arctic snow exposing dark surfaces that heat up and cause further melting is an example as the initial melting leads to more melting. Birds migrating is a response to changing seasons, a thermostat is a negative - feedback mechanism, a pond becoming acidic is a one - way change due to pollution, and predator - prey dynamics are a complex ecological interaction but not a positive - feedback loop in the same sense.

Answer:

E. is melting arctic snow exposing dark surfaces that heat up and cause further melting