The symbiosis between a Pistol shrimps and gobies is called Mutual symbiosis. <u>In this process both animals benefit. </u>The shrimp creates and maintains a burrow for both the animals to live in, where as the fish offers protection from predators. When outside of their burrow the fish keeps a keen eye to spot any predator around and sends a warning to the goby through flicking of its tail in cases of a predator approaching.
 
        
                    
             
        
        
        
Mitochondria is the powerhouse of a cell
        
                    
             
        
        
        
True. Otherwise we would never stop growing although broken bones regain cartilage into solid bone when we break one but it doesn’t expand.
        
             
        
        
        
Answer:
B. DR, Dr, Rd, dr
Explanation:
This question involves two genes. Alleles D and R are dominant over alleles d and r. These two genes obey the law of independent assortment as proposed by Gregor Mendel. 
Based on the question, a genotype RrDd will produce the following combination of gametes following the process of meiosis:
DR, Dr, dR, dr