Answer:
The answer is option A: layers 
 
        
             
        
        
        
Explanation:
Many birds, such as geese, seasonally fly to warm places when the weather gets cold. They then return when the weather warms. This process is called migration. ... Migration enables many animals to move to places where it is easier for them to survive.
 
        
             
        
        
        
The answer is chromosomes
        
                    
             
        
        
        
Answer:
According to the image, the approximate QT interval is 0.4 seconds.
Explanation:
The QT interval is the space between the beginning of the QRS complex and the end of the T wave, which represents from the beginning of depolarization to ventricular repolarization.
Considering that the extandardized measurements of an EKG, where the paper circulates at a speed of 25 mm/s, 1 mm horizontal —measuring time— has an equivalence of 0.04 s.
In the image, there is 10 mm between the beginning of the QRS and the end of the T wave, so:
     0.04 seconds X 10 mm = 0.4 seconds.
Then, the estimated QT interval is 0.4 seconds.