The Shang Dynasty developed in HwangHo.
Let's first think what could be a "positive" impact - this would mean making the environment more clean and more friendly towards other species.
So they could clean up the environment (from the mess that was likely introduced by a human activity) and support other organisms in it - for example by removing the physical barriers for migration of other species (bridges over the streets for example) <span />
I believe C is the correct answer
The definition for alliance is a treaty or formal agreement of two nations to cooperate for certain purposes. It is also the state of being allied. Members of alliance are called allies.
They join together to fight common enemies. They arise from states attempts to maintain equal power between them.
