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:
First, the options:
A. Midazolam
B. Ketamine
C. Nitrous Oxide
D. Bupivacaine
The ANSWER is A. 
A. Midazolam
Explanation:
A. Midazolam✔
Midazolam is mainly used for amnesia or sedation in many diagnostic, therapeutic, and endoscopic activities or procedures. 
B. Ketamine ❌
It has higher risk of side effects. 
C. Nitrous oxide ❌
It won't be preferable for this case, since it can not be breathed in during a bronchoscopy. 
D. Bupivacaine❌
This is solely for local anesthesia.
 
        
             
        
        
        
Heterozygous means 2 different zygotes. Since Smooth kernels are dominant, Zygotes KK and Kk will be smooth and kk will be wrinkled.
If you were to set up a Punnett Square chart like: 
            K     k
    K   (KK)    (Kk)
    k   (Kk)     (kk)
the ratio for smooth to winkle would be  3 : 1
Which Will be 75% Smooth  and 25% Wrinkle
 
        
             
        
        
        
Answer:
There you go! they explained it better than I could. hopefully that helps you, for more information you could simply look up an article.