Answer:
The deep and complex troughs that make up Puget Sound were carved by glaciers
The Sound has remarkable patterns of water circulation that support its thriving ecosystem, and which give rise to water quality problems such as hypoxia.
and seattles natural features changed by humans were probably changed because its a city bulit of hills around all of the water and it gradually growed from time and started to add rail roads and more buildings with more people but im not to sure
Explanation:
hope this helped:)
