I found a similar question. If the attached document is the same as your supposed question, then my answer are below.
AV valves open - atrial pressure is greater than ventricular pressure
AV valves closed - Ventricular pressure rises above atrial pressure
Semilunar valves closed - ventricular pressure is lower than arterial pressure
Semilunar valves open - pressure in the ventricles is greater than the pressure in the great arteries
 
        
        
        
Area code 917 is a telephone area code for all five boroughs of New York City (Brooklyn, Manhattan, Queens, Staten Island, and the Bronx).
        
             
        
        
        
Answer:
Secondary succession
Explanation:
A secondary succession is when a type of disturbance happens when there is <em>already </em>soil present. In this case, it has already started out with a forest (including plants, trees, and wildlife). Other examples of a secondary succession include a wildfire, hurricane, flood, or human destruction. 
This is different from a <em>primary succession</em>. A primary succession occurs when  there is <em>no</em> soil present.