Answer:
B. How efficient can an engine be, in theory?
Explanation:
They give us informations about our ancestors and how did they live and what did they do and than compare it to present way's of life.
Answer:
C
Explanation:
The water cycle is powered by heat from the Sun that allows water to change phase. Solar heating causes surface water to evaporate and join the atmosphere as water vapor. The water vapor then condenses to form clouds and, depending on the height of the clouds and the latitude, falls as solid or liquid precipitation back to the surface.
Without solar heating, all the water on Earth would freeze solid and there would be no atmosphere or rain.
The length is 88 cm, multiply the width by two and subtract it from the whole perimeter. Then divide the whole perimeter again by two to find the length of one side.
