The red-green color blindness is a recessive X-linked trait. The females are not affected unless both the X chromosomes have the affected allele. Mostly, the females are the carriers, and the males are affected as they have only one X chromosome. In the given pedigree, the father of Irene have the normal allele, while her mother is a carrier. However, Irene is neither a carrier nor affected. This means that she carries normal alleles on both X chromosomes. Hence, her allele combination is  .
 .
 
        
                    
             
        
        
        
The question is not clear
        
             
        
        
        
Answer: They do affect the health of an ecosystem.
Explanation: In an ecosystem there are many things that are biotic and abiotic. For an example: water is abiotic and plants/animals are all biotic, the water is not living but it keeps the ecosystem alive by quenching the thirst of the plants growing from the ground and the animals roaming around on the land. Dead animals and plants are not abiotic and they are now providing food for fungi and bacteria. Without the abiotic factors, it would be difficult for the biotic to survive. 
 
        
             
        
        
        
It is d, a substance that participates in a chemical reaction. You can also tell it just by looking at the stem of the term :)