Answer - Cyanobacteria aka Algae that contributed in creating O2 for the atmosphere as a byproduct thru Photosynthetic.
Reason - Of course Algae make up mainly the whole world in waters and they do photosynthesis to give off oxygen in the atmosphere.
        
             
        
        
        
"The mutant will not be able to grow on lactose" is the one thing among the following choices given in the question that will be observed if mutation occurs in the gene for the lac repressor and results in a repressor thatdoes not bind lactose. The correct option among all the options that are given in the question is the first option.
        
             
        
        
        
Hot , dry weather is the answer
        
             
        
        
        
Answer:
The answer is Eurasia, North America, Africa, and South America.
Explanation: