I believe The answer is A)Two or more substances that are mixed together but are not chemically combined .
The answer is Human
While the other options are always affecting the ecosystems, humans have a greater affect than all of the above
Our actions are not wrong because there is an ethical difference between treating people as a means and treating them merely as a means to achieve some end. This is the concept behind the Kantian ethics also referred to as means to end principle.
Answer: C) The seasons if the rivers that ran through each empire.
Explanation: All of these civilizations started near a river, if the river were to be removed, then the cilvilization woulden't and can't survive.
