The pollution from the Industrial Revolution darkening the trees. After the trees darkened from all the soot in the air, the white moths were easier to see and more vulnerable to predators. The dark moths blended into the dark tree bark.
        
                    
             
        
        
        
<h2>Permanent tissues in Plant</h2>
Explanation:
A) The cell walls of parenchyma cells are thinner than those of sclerenchyma cells
Plants posses basically two kinds of tissue- meristematic tissue and permanent tissue.
Meristematic tissue is made up of cells which are capable of active division and give rise to other tissues,.
Permanent tissue are already differentiated and usually do not divide.
Permanent tissues are -collenchyma, sclerenchyma and parenchyma.
Parenchyma and collenchyma are living whereas sclerenchyma is non-living.
 
        
        
        
<span>The cell has 1% concentration of the salt. The external environment is highly concentrated with 25% saline solution. This will lead to release of water outside the cell, by passive diffusion from a region of high conentration of solvent to lower concentration. Thus, the cell will shrink.</span>
        
                    
             
        
        
        
Yes biotic means living or once living. it was living at one point so yes its biotic