For the first question, i think the correct answer is A. Normal cells undergo apoptosis while cancer cells don't. For the second question, The answer is option B.<span> </span><span>Cell division has two checkpoints namely, G1
checkpoint and spindle assembly checkpoint. The checkpoint which determines if
division has properly occurred is the G1 checkpoint. At this point, is a damage
in the DNA is detected or the has not reach the optimum size, the cell is
stopped in G1 and is not allowed to proceed to further process.</span>
 
        
        
        
Answer:
<u><em>definition;</em></u>
enzymes are protein that catalyze speed up the biochemical reactions and are not changed during the reaction . the molecules at which enzyme work  are called <em>substrate </em> and enzymes convert them into  different molecules called products.
<em><u>benefits of enzyme in digestion ;</u></em>
enzyme lower the activation energy in several ways. they may alter the shape of substrate and reduce the requirement of activation energy . enzyme may also  lower activation energy by bringing substrate in correct orientation to react . enzyme break down <em>carbohydrates, lipids and  proteins  </em>which are component of human food .In digestion larger molecules are broken into smaller molecules like amino acids ,simple sugars ,fatty acid ,vitamins ,salts and water to provide to cells.  these molecules are  a part of larger molecules like protein ,polysaccharids  and lipids . enzymes like amylaze, lypase   ,salivary amylase, pepsin ; it is a very strong protein digesting enzyme it is released in its inactive form pepsinogen  which is converted into pepsin with the help of H-C-L  hydrochloric acid it takes part in digestion in stomach