Answer: Separately derived system
Explanation: A separately derived system is used to describe a premise wiring system whose power is derived from a source of electrical energy such as transformer, solar photovoltaic cell or generator. A separately derived system has no direct connection to any conductor from another system or doesn't generate it's power from any direct connection to a conductor from another system or source except those from established from bonding or grounding connections. Separately derived systems usually generate it's power on it's own. 
 
        
             
        
        
        
The middle or centre of the Earth is the core. However the middle of the layers from the surface to the centre of the Earth is known as mantle. 
        
                    
             
        
        
        
Answer:
<h3>The answer is option B</h3>
Explanation:
The frequency of a wave can be found by using the formula

where
c is the velocity
From the question
wavelength = 0.39 m
c = 86 m/s
We have

We have the final answer as
<h3>200 Hz</h3>
Hope this helps you
 
        
             
        
        
        
Answer:
b. a lens does not focus all colors of light to the same place.
Explanation:
Chromatic aberration is a defect of a lens. In this defect, the lens is unable to focus the different wavelengths of the light on a single focal point. It is also known as chromatic distortion and color fringing. It is caused by the dispersion of light while passing through a lens. As a result, the image might become blurred and different colors are observed around its edges. It can be corrected by the use of a combination of converging and diverging lenses.
Hence, the correct option will be:
<u>b. a lens does not focus all colors of light to the same place.</u>
 
        
             
        
        
        
Answer
A
Explanation
The light the fish absorbs is sunlight, the light reflecting is UV