Length of the cord..........................................................
        
                    
             
        
        
        
The change in distance is 30 because if you subtract both number you'll get 30
        
                    
             
        
        
        
I think its A I hope this help thank you!!
        
             
        
        
        
Answer:
Decreases the transparency of the atmosphere to infrared light. 
Explanation:
When a large amount of green-house gases are present in the atmosphere, the layer of these gases become opaque to infrared radiation and radiation from the sun get trapped into these gases molecules. These excited molecules radiate this energy into our own atmosphere and that why the temperature of Earth is rising due to the Green-House effect. 
 
        
             
        
        
        
When someone lifts a book from the ground, the work you use is positive. By lifting the book, you change it's energy and it's original place The book gains, kinectic energy.
Hope I helped.