Electrical conductivity tester. 
If the bulb begins to glow brightly when the plug is submerged in the unknown solution then the solution has high conductivity. 
The bright glow of the bulb resulting from the experiment indicates that the current flows easily through the unknown liquid.
        
             
        
        
        
Answer:
True 
Explanation:
The stratosphere is the layer of the earth’s atmosphere which is above the troposphere and below the mesosphere.
The stratosphere contains about 90 percent of the ozone layer. The stratosphere is made up of ozone layers which helps in the absorption of about 95 percent of the ultraviolet rays from the sun and converting to heat. 
This is the reason why depletion of the ozone layer found in the stratosphere gives rise to global warming.
 
        
             
        
        
        
  <span>are we talking human reproduction? in this case only 1 egg is implanted. in unusual cases there could be 2 eggs implanted meaning fraternal twins. if 1 egg splits, we get identical twins. with only one egg implanted, there is only 1 kid being produced. 
the female has eggs stored from birth. 1 ovary 'pops' once a month to either be discarded via a period or implanted after fertilization. multiple eggs released is usually the effect of fertility drugs making many eggs get released at once. this is unusual unless fertility drugs are in use</span>
        
             
        
        
        
Maybe they came from different groups or mixed semen