Answer:
First question: The United Nations issued a hybrid United Nations-African Union mission (UNAMID) to maintain peace in Darfur. It was established on 31 July 2007 with the adoption of Security Council resolution 1769. However, it formally took over on 31 December 2007.
Second question: As said above, international countries attempted to mediate peace in Darfur and helped. There is still conflict in the Darfur region but it is much lower than before and has grown much more stable. 
Explanation:
Had been explained above. 
 
        
             
        
        
        
    Continental air masses are characterized by dry air near the surface while maritime air masses are moist.
    Polar air masses are characterized by cold air near the surface while tropical air masses are warm or hot. Arctic air masses are extremely cold.
 
        
             
        
        
        
Answer:
An Anticline has a form of an A, it means it is curved upward
A Syncline has a fomr almost like a Y, (actually is like a U), it means it is curved downward
Explanation:
Originally, sedimentary rocks are horizontal beds where the deepest bed is the oldest and the youngest bed is the surface one.
After stress by tectonics, these rock beds become curved and we can find upward and downward curves. Usually, these folds are exposed on earth's surface, then they are exposed to weathering and erosion, which make disappear part of the secuence of rock beds.
An anticline can lose it's summit, so we will find a repeated secuence where the oldest rocks are in the central part (the axe) and the youngest are in the external parts of the fold.
A syncline will show the youngest rocks in it's axe and the oldest rocks in its external parts.
 
        
             
        
        
        
Population change 
Explanation:
The change in the number of people living in a city, county, state, province or nation is generally referred to as population change. 
Population change is positive when there is an increase in population;
Population change is negative when there is a decrease in population. 
- Population is dynamic and it changes over a length of time. 
- Migration is one of the leading cause of population changes. 
- When people move away from an area, it is called emigration. It is a negative population change
- When people moves to an area, it is positive population change called immigration. 
- Other cause of population changes are war, vices, economy, employment opportunities, education etc. 
learn more: 
Population brainly.com/question/6233803
#learnwithBrainly
 
        
                    
             
        
        
        
Answer:
Because it was once just ocean
Explanation:
The earth was just ocean