You esophagus is your throat. 
        
                    
             
        
        
        
What are the choices? But Carbohydrates are the main component of fruit and vegetables.
        
             
        
        
        
Mitochondria important for the cell that can't survive without it but blood cell is an exception. Blood is a tissue in animals so RBCs are animal cells and don't have mitochondria
        
             
        
        
        
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. 
 
        
             
        
        
        
Answer:
B. As the distance between loci increases, some multiple crossovers go undetected such that the relationship between recombination frequency and map distance ceases to be linear.  
Explanation:
When calculating recombination frequencies, and hence, map distances, we might notice that these distances are not completely additive. They might vary. <em>For example, let us say that we have three genes, A, B, and C, in that order. </em>We calculated that the <em>distance between A and B equals 5.9</em> MU and that <em>B and C are 19.5 MU apart.</em> According to this, we might say that the <em>total distance between A and C is 25.4 MU (5.9 + 19.5). </em>However, after a<em> two-point calculation between A and C, the value equals 23.7 MU. </em>
The recombination frequency between these two genes located in the extremes and far apart underestimate the actual genetic distances between them because there might occur other crossing-overs that were not detected. This is <em>when calculating the distance between A and C, we probably will not detect the occurrence of a double recombinant between them, and hence, we might sub-estimate the real distance.</em>
The relationship between the actual map distance (number of crossing overs) and the recombination frequency between two loci, is not lineal. The farther apart are the two genes, the worse is the distance estimation.