Mostly any bug you can think of
Compositional layers are determined by their components, while mechanical layers are determined by their physical properties.
B would be your answer hope this helps :)
I do not think the industrial and agricultural revolutions could have occurred without the environmental costs. The industrial revolution in the 18th century occurred at a time in history when people where not aware of the consequences of their actions or the consequences of the widespread use of fossil fuels. Even if they were aware the technology would not have been present to harness power from natural renewable sources of energy.
