They adapted to their environment by wearing light, linen, and loose hanging robes to help from getting to hot. They adapted their clothes to the weather of their environment.
They modified their environment by using the system of irrigation. Irrigation was a type of sewer or drain which would be dug into the ground connected to a river to easily bring water to crops and land. This is modification because they used what they already had and made it into something they could use.
They depended on their environment for water. The reason why Ancient Egypt was able to thrive was because of the nearby Nile River which gave them water to drink and water their crops with. Without it the land wouldn't have been fertile and there would've been no water for them to survive on.