Answer: District committee takes action for the welfare of district of any state. Depending upon the number of districts each state may have many district committees to look upon the welfare. 
Explanation:
The following are the conditions in which the positions of the members of the district coordination committee remains vacant:
1. The member have left the committee or had given resignation. 
2. No elections have been conducted for new appointment. 
3. The member have been suspended from the post.
4. The member had taken long leave due to health or other issues. 
5. The time the member left the committee to the time of election had a long span. 
 
        
             
        
        
        
The answer is b. social clock
Social clock refer to the social expectations that are
given by a culture about when the transitional events like marriage, having
kids, or retirement should take place in life. The social clock for every
culture and country differs, as the norms and values of every society have been
shaped over several centuries.
 
 
        
             
        
        
        
Answer:
planting crops in curved lines to prevent erosion
Explanation:
Since, every place was fertile there was no need to plant it in a curved manner.
 
        
             
        
        
        
Individuals around the world are about 99.1% genetically identical