Question

Describe two changes that are harmful. Explain why you consider them harmful how can you prevent them.

Answer 1

Rusting of iron: If bicycle's chain gets rusted it may result in the breakage of it.  

Prevention: Coating the iron surface with grease.

Melting of glacier (physical change): It may result in the rise of ocean level resulting in the submerging of islands and coastal areas.  

Prevention: Reducing the emissions of green house gases.