ALL of them...................... 
 
        
                    
             
        
        
        
Answer:
The right atrioventricular valve (tricuspid) regulates the opening between the <u>right atrium</u> and the <u>right ventricle</u>.
Explanation:
Valves are gates that allow the connection between atria and ventricles. The two valves located on the right side (tricuspid and pulmonary) direct the incoming blood from the body to the lung, where it is oxygenated; from there it returns to the left atrium, to later pass through the mitral and aortic valves. The left atrium connects to the left ventricle through the mitral valve and the right atrium connects to the right ventricle through the tricuspid valve. 
 
        
             
        
        
        
Answer:
Lungs.
Explanation:
Lungs are the organs that are responsible for gaseous exchange in humans. The lungs absorb oxygen from the air that is required for the process of respiration while on the other hand, carbon dioxide is transferred from the cells to the lungs through blood because carbondioxide gas is a waste material that is produced during respiration so it can be removed from the body with the help of lungs..
 
        
             
        
        
        
The 2% of the insects will begin to reproduce and grow their population exponentially and in time enable the population to recover. This is if the population is large enough to enable random mating. The 98% reduction in population drastically reduces competition for the remaining individuals hence giving them abundant resources for them to thrive.   
 
        
             
        
        
        
Answer:
The muscle has two, three, or four origins, respectively.
Explanation
- A muscle is an organ composed of muscle tissue that contract to facilitate a particular movement
- biceps,triceps and quadriceps  are types of skeletal muscles since they use bones as levers
- <em><u>They differ in that; the biceps have two origins, triceps have three origins and quadriceps have four origin.</u></em>
- <em><u>Bicep is a two headed muscle thus said to have two origins ,triceps have three muscle heads and therefore have three separate origin attachment point while quadriceps are made of four muscles heads hence have four origins. </u></em>