There are a few different answers to this question, depending on what you are asking. I'll go over the main ones.
1. The Earth's axis is tilted in comparison to the Sun, so days get shorter in the winter months. This is due to less light, and therefore energy, hitting the Earth directly. Instead, that energy either misses entirely, or hits nearer to the Equator. This is why the poles have twenty-four hour days and nights depending on the season. (Night in the winter, day in the summer.)
2. In terms of the food chain, energy from the sun is converted to basic sugars by plants in a process known as photosynthesis, inside the plant's cloroplasts. Small animals such as mice and insects consume the plants, and the energy those plants converted from sunlight. This continues up the food chain until you get to apex-predators (tigers, bears, wolves, owls, etcetera).
3. In terms of electricity, solar panels are made of tons of 'solar cells' which tend to be lots of silicon atoms, which like to share electrons, and a conductive backing. (Pardon me if some of this section is incorrect, I only have a basic understanding of solar panels) When a photon (that is, a light particle) hits the silicon, it bumps off an electron, and the conductive backing catches it, resulting in a electrical current. This current is incredibly small per solar cell, so you need a ton of them to make any sort of useful power out of them. Solar panels do degrade over time, but incredibly slowly, there are some from the 1970's that still generate just as much power as they did originally (if not, only ever so slightly less).
I hope I answered what you needed to know! If you wanted a different answer, feel free to comment with some clarification and I would love to fill you in :)
        
                    
             
        
        
        
Solution :
The type of melting that is responsible for the mafic magmas for the following plate tectonic settings :
a). Mid - ocean ridges
At the mid oceanic ridges, the two plates diverges away and the new oceanic crust is formed by the effusion of the magma. The earth's interior is exposed as the two plates are moved away.
b). Continental rift :
A new oceanic crust is formed by the effusion of the magma and the two plates diverges away. Thus it causes the formation of the melt in the continental drift. As a result, the crustal thickness decreases.
c). Oceanic and continental volcanic arc :
The oceanic arc and the volcanic arc are the locations of the convergence. The denser plate of the arcs subducts under the less denser plates or the  lighter plates and it moves downwards into the mantle, which causes the increase in temperature of the surroundings. 
 
        
             
        
        
        
Answer:
I don't think it was because your room wasn't clean. The main cause of bed bugs is travel, which means most likely you got one on you when you went outside or something, and you accidentally got it into your room. Bed bugs hitchhike on luggage, clothing, people, etc. 
If there are blood stains or dark/rusty spots on your bed/pillow, there are definitely bed bugs. The bloodstains/spots come from you crushing the bed bugs accidentally. The place where bed bugs are (in this case, your room), may also begin to smell bad. You might also see eggs laid by the bed bugs. 
Let me know if you have any other questions. Good luck!
 
        
             
        
        
        
It is absolutely true that China is seeking to lessen its dependence on coal by developing more hydro power resources. The correct option among all the options given in the question is the first option. China is blessed with natural rivers and it is slowly trying to reduce its dependence on coal powered plants to hydro power plants. This is also a great step towards reducing air pollution.
        
             
        
        
        
matias may live farther away so its  0.7 kilometers.
jack may live closer to the bookstore so it may only be 0.5 kilometers.