Climate: is the long-term average of weather, typically averaged over a period of 30 years. D is the answer
        
             
        
        
        
It's C, the catalyst remains unchanged through a reaction. 
        
                    
             
        
        
        
Answer:
Option C
Explanation:
The null hypothesis is the problem statement and alternative hypothesis is counter of the null hypothesis. 
Hence, the null hypothesis here is the rate of extinction was neither higher nor lower when there were sudden climatic changes (asteroid strike)
And alternate hypothesis is "the rate of extinction was either higher or lower when there were sudden climatic changes (asteroid strike)"
Hence, option C is correct
 
        
             
        
        
        
By using ratios. You get a punnet square and then get the ratio or even the percentage.