Answer: b. can lead to other cardiovascular diseases
 
Explanation:
High blood pressure or hypertention can be define as a condition in which the flowing blood exerts force over the walls of the arteries. The arteries are the type of blood vessels which carries the blood from the heart to the rest of the body parts. This condition results in heart diseases like heart stroke or heart attack due to abnormal blood flow. 
 
        
             
        
        
        
It has two strands 
Hope this helped :))
        
             
        
        
        
Answer: 2 covalent bonds
Explanation: 
In H2O molecule, two water molecules are bonded by a Hydrogen bond but the bond between two H - O bonds within a water molecule are covalent. The dotted lines represent a hydrogen bond and the solid lines represent a covalent bond.