The natural environment has been strained by

The natural environment has been strained by growing urban population.
Growing urban population lead to the increase in consumption for manufactured products such as automobile, hairspray, plastic bags, etc.
Products like this often resulted in pollution that create strain for natural environment.

Bob: coke is baby pandas.jim: what? how do you figure that coke is baby pandas? bob: because this book says so.jim: how do we know the book is correct? bob: because it says that coke is baby pandas.jim: how does that prove the book's accuracy? bob: because it's statement involving coke and baby pandas is correct, therefore it is accurate.jim: how do we know that it's correct? bob: because we have concluded that the book is accurate, and therefore the statement is correct.therefore, coke is baby pandas.