Human activities are comprised of many things which can destroy as well as endanger the environment and nature surrounding us. They are: coal mining (fossil extraction), factories, vehicles etc. They can pollute our environment and can destroy the nature and the animals. 

They can also improve things. 
Create fertile land where none existed for instance. 

Human activities that damage the environment:
Burning fossil fuel is damaging the environment which producing carbon dioxide that makes global warming.cutting trees is damaging the environment because it absorbs carbon dioxide and give out oxygen.polluting water fishes that we eat and might bring diseases.Driving cars gives out carbon dioxide.