This is why S-waves arrive as secondary waves at the Earth's surface. There is another importantdifference between P-waves and S-waves. Although both can pass through solid rock, only P-waves can also pass through gases and liquids.
        
                    
             
        
        
        
D all of the above, they all contribute to seasons
        
             
        
        
        
Answer: 1- Option (D)
               2- Option (A)
Explanation:
The green house gases plays a significant role in the earth's global temperature. In absence of green house gas, the earth would have been very much cold and life would would be difficult to exist. The average global temperature would have been about -15°C to 25°C. So the most favorable answer given here is that the<u> earth's temperature would have decrease by about 60°C</u>.
<u>Carbon dioxide (CO₂) is not the most abundant green house gas</u>. It is the second most abundant. The present composition of CO₂ in the atmosphere is about 0.04% by volume. A small increase in the CO₂ level, can lead to a global rise in the temperature. Hence, <u>the above statement is false.</u>