Looking at the following answers, and considering the definition of a biological community I believe the answer is D.
Answer:
Explanation:
solar cell - converts sunlight into electricity
geothermal energy - heat produced within the Earth
wave energy - turns turbines along coastlines
hydroelectricity - water falling through dams turns turbines, generates electricity
A mole is a unit to describe an amount of something/specific substance. Typically standard for measuring a large quantity of small entities like atoms, molecules, or other particles.
C. a chemical reaction occurred when the two liquids were mixed
When sodium amide i.e.
reacts with water i.e. 
results in the formation of sodium hydroxide i.e. 
and ammonia 
.
The chemical reaction is given by:
Now, when ammonia i.e. reacts with water results in the formation of ammonium hydroxide i.e. 
The chemical reaction is given by:
Thus, the products of the above reactions are ammonia and ammonium hydroxide (without sodium ion).
The structures of the products are shown in figure (1): ammonium hydroxide and figure (2) ammonia.
