Answer:
A) The radial orientation of cellulose microfibrils in the cell walls of guard cells causes them to bow outward and open when the stomatal pore when turgid.
Explanation:
Stomata are pores on the surface of leaves that work as valves controlling the gas exchange in plants; they are bordered by a pair of curved guarded cells in charge of opening and closing by increasing or decreasing the stomatal pore area. 
Guard cells walls structure consist of a combination of stiff cellulose microfibrils oriented along the circumference of the cells and a softer matrix material which makes it possible for stomata pore to open by increasing water pressure (turgor).  
Option B states that when guard cells become turgid, they close the stomata. This is a false statement as we explained before. 
Option C states that light (known stimulant for opening stomata) causes guard cells to become flaccid which is also false. Guard cells become turgid in order to open the stomatal pore. 
Option A is correct.
 
        
                    
             
        
        
        
The answer to your question is D, a decrease in oxygen levels in the blood during exercise. 
Hope this helps! 
 
        
             
        
        
        
The most appropriate postoperative
feeding regimen is; the mother should start feeding the infant with a small quantity of the formula and it should be done slowly
to prevent the infant from vomiting which is likely to occur after the first
feeding and to also ensure that the infant burp frequently.
        
             
        
        
        
Immunotherapy, also called biologic therapy, is a type of cancer treatment that boosts the body's natural defenses to fight cancer. It uses substances made by the body or in a laboratory to improve or restore immune system function. Immunotherapy may work by:
Stopping or slowing the growth of cancer cells
Stopping cancer from spreading to other parts of the body
Helping the immune system work better at destroying cancer cells
There are several types of immunotherapy, including:
Monoclonal antibodies and tumor-agnostic therapies
Non-specific immunotherapies
Oncolytic virus therapy
T-cell therapy
Cancer vaccines
Hope this helped :)