- decreases as altitude increases
- results from a column of air pushing on an area
- decreases due to fewer air particles pushing down
Pressure is the force exerted, by a substance, per unit area.
Explanation:
Pressure is given by the formulae;
P = F/ A
Whereby;
P = pressure
F = Force
A = area
Remember that ..
F = Ma
Whereby;
F = Force
M = mass
a = acceleration
Therefore pressure can be given as;
P = Ma / A
The mass of the above column of a substance multiplied by the acceleration due to gravity = pressure exerted by the substance. 
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<span>The answer is A. Variation in gene pool
Speciation is a formation of a new species during the evolution line.
When there is a variation in a gene pool, a unique combination between genes could be formed during the mating process. This will create an offspring with unique gene pool that will lead to speciation</span>
        
                    
             
        
        
        
<span>Meristem cells divide and some of the new cells differentiate into xylem and phloem. </span>
        
             
        
        
        
I think it’s IBi
i’m sorry if it’s wrong
        
             
        
        
        
Answer:
pluripotent
Explanation:
A cell that can differentiate into all cell types of the adult organism are called 
"pluripotent". Like cells are named meristematic cells in higher plants and embryonic stem cells in animals, though some groups report the presence of adult pluripotent cells.