Answer:
1. physical and chemical barriers
2.non-specific innate response
3. specific adaptive responses
Explanation:
 
        
             
        
        
        
The middle turqois-ish color is Nucleus 
The one on the bottom right is cell membrane
The one on the bottom left is cell wall
        
             
        
        
        
The correct asnwer to your question - why would a group of antelopes leave the herd for search of a better grassland is an example of emigration - B.
These antelopes would emigrate to a certain grassland and be immigrants in that grassland. This has to be distinguished. 
        
             
        
        
        
Answer:
1. 6.56 km/hr
2. 1.83 m/s
Explanation:
The average velocity/speed can be calculated using the formula;
Average speed/velocity = distance/time
According to the information provided in the question, distance = 12.5km, time = 1.9h
Average velocity in km/hr = 12.5/1.9
= 6.578
= 6.56km/hr
However, in order to calculate the average speed in m/s, we have to convert distance in km to m, and time in hour to seconds. 
1km = 1000m
12.5km = 12.5 × 1000
= 12500m
1 hour = 3600seconds
1.9hours = 1.9 × 3600
= 6840seconds
Average velocity = 12500/6840
= 1.827
= 1.83m/s
 
        
             
        
        
        
The best answer would be:
 
Osteoarthritis
 
<span>It is when the person experiences too much weight bearing activities, which may cause the wear and tear breakdown of the joints. This worn bone may be a foreign material when identifying the joint erosion.</span>