I believe the biosphere is fragile, because over time all of the pollution us humans have made; If its from air pulloution, acid rain or even water pollution. the toxic acids over time have made the biosphere and the ozon layer weaker and more thin. which causes the biosphere to become weaker.
        
                    
             
        
        
        
Answer:
a. Two of these are correct. 
Explanation:
The two correct options are
b. Is a critical component or requirement for wound healing to take place
d. Existing blood vessels give rise or sprout to form new blood vessels
Angiogenesis is the physiological means in which new blood vessels form pre-existing vessels, developed in the starting phases of vasculogenesis. Angiogenesis is a usual and important process in growth and development, wound healing and in the development of granulation tissue.
The growth and maturation of blood vessels is a largely regulated multistep mechanism called angiogenesis.
 
        
             
        
        
        
Salt molecules are much smaller than starch molecules and can pass through more easily. ... Thus, they are quite large molecules in contrast to the relatively small salt molecules. The smaller salt molecules pass through the membrane easily, but the larger starch molecules cannot pass through the membrane.