Levees and embankments allow humans to c)settle below river level. A levee is defined as "an elongated naturally occurring ridge or artificially constructed fill or wall, which regulates water levels." This definition can also be used for the term embankment.
Answer:
I believe the answer to this question would just be gravity
D. They do not produce electricity.
Passive solar heating is a technique where the sun's energy
is used for heating spaces. It does not generate electricity but can save substantial
electricity by making use of thermal mass. Materials that have a high density
such as concrete and bricks absorb and store electricity. Along with operable windows
and thermal chimneys, thermal mass is being
utilized to take advantage of sun exposure.
