Introns because they are coding sequences.
Exons because they are non-coding sequences.
        
             
        
        
        
Answer:
Elements that are the border line of metals and non-metals.some elements near the stepped line have mixed properties of metals and non-metals these elements are called metalloid e.g. Silicon and Germanium
Explanation:
I hope this will help you:)
 
        
             
        
        
        
Answer:
D, form rings and chaines i think
Explanation:
This allows the Carbon to form long chians with elements such as hydrogen and phosphorus, etc, used some info from this site
https://courses.lumenlearning.com/wm-nmbiology1/chapter/carbon-and-carbon-bonding/
if my answer helps please mark as brainliest. 
 
        
             
        
        
        
Answer;
petit arm 
Explanation;
All human chromosomes have 2 arms, the p (short) arm and the q (long) arm. They are separated from each other only by a primary constriction, the centromere, the point at which the chromosome is attached to the spindle during cell division. 
The symbol "p" stands for "petit", small in French, while "q" was chosen merely because it was the next letter in the alphabet.