All cells have a cell membrane. its basically what protects the cells from getting toxins that are sometimes entering your body. without a membrane on all cells, you would get sick a lot!!
Answer:
alveoli
Explanation:
They are the smallest structures in our lungs where capillaries exchange O2 and CO2 in blood.
The word sponge is more appropriate to use than Underground river since an underground river can loose water while an aquifer cannot loose water, unless it is open-air and above ground. then the aquifer would slowly loose water due to evaporation from the sun.
Answer:
Winding mills are made on hills because of air flow and currents.
Explanation:
Winding mills capture wind to turn blades and produce energy. In order to do so, it needs winds! Strong winds, in order to turn the blades. You will notice that if you ever scale a mountain or go higher, it starts to become windier/the wind blows harder.
If the wind mills are placed higher, it can capture these windier conditions, thus moving the wind blades to produce energy. The higher the hill, the stronger the wind current, the more energy it produces.
