Answer: For decreased chances of rejection 
Explanation: 
The three higly polymorphic MHC 1 genes in human beings are HLA-A, HLA-B and HLA-C.
These determine the compatibility of the organ or tissue in the recipient's body each by the help of many alleles that segregates in a population.
There are very less chances that a random chosen donor will match the a recipient six allele genotype.
This is the reason parent  may be the best donor for organ transplantation or tissue transplantation.
 
        
             
        
        
        
The answer is C because it is the only one that makes sense to that question. 
        
             
        
        
        
Because of photosynthesis
        
             
        
        
        
Answer;
Two recessive alleles are the number of alleles that a person must have to have albinism.
Explanation;
When a trait is recessive, such as albinism, an individual must have two copies of a recessive allele to express that particular trait. Recessive alleles are denoted by a lowercase letter , such as b versus B. Only individuals with a bb genotye will express a recessive trait, hence, the offspring must receive one recessive trait from each parent to exhibit the recessive trait.