I believe it is A (Adenine)
        
                    
             
        
        
        
Answer:
(C)cell nuclei that contain DNA
Explanation:
They are eukaryotic, which means they have a nucleus. Most have mitochondria. They can be parasites. They all prefer aquatic or moist environments.
 
        
                    
             
        
        
        
Answer:
A single gene on the Y chromosome plays a crucial role in the parental development of the testes. 
Explanation:
Y chromosome is present only in males and this chromosomes is the distinguishing factor which separates males from females. It is the smallest chromosome but of utmost importance due to its sex determining feature. Up till now, studies show that Y chromosomes only carry limited amount of genes.  
The Y chromosome, most importantly, comprises of the SRY gene. This is the gene responsible for determining the testis and for the development of the testis. The SRY gene is responsible for sex determination. 
 
        
             
        
        
        
<span> water is a solvent. It helps to break waste and nutrients down in the </span>cell so <span>that they can be moved through the various membranes. this is necessary in a cell </span><span />