Where in a river would you find fish that are adapted to low light and low oxygen levels?

According to the tide table below what time of day will the highest tide occur?

What are atoms of the same element with varying number of neutrons

Imagine you are standing in the antarctic during the southern hemisphere summer. the sky is clear and blue. there are no clouds in the sky. your shadow is cast on the icy ground. what is the color of the shadow?