Answer:
The correct answer is -transfer fixed carbon dioxide to cells in which the Calvin cycle occurs
Explanation:
In C4 plants the light reaction and Calvin cycle occurs in two different cell that are mesophyll cell and bundle sheath cells. First, the CO₂ is fixed into 4- carbon oxaloacetate by an enzyme PEP carboxylase.  
Then this oxaloacetate is converted into a simpler form called malate. Malate molecule then enters into bundle sheet cell and there it releases one molecule of CO₂. This CO₂ enters the Calvin cycle which results in the sugar formation with the help of enzyme rubisco.
Therefore by releasing of CO₂ molecule by malate in bundle sheet cells, it transfer fixed carbon for the Calvin cycle to occur.
 
        
             
        
        
        
The part of the Human body that is most similar in function to the spongy mesophyll layer in a leaf is A) Alveoli in the lungs.
        
             
        
        
        
Answer:
The correct option is: <em>a deficiency of dopamine in the substantia nigra.</em>
Explanation:
The substantia nigra is the principal site involved in the physiopathology of Parkinson´s disease. 
Cells from this area degenerate and die progressively causing important degeneration in the central nervous system. The cells that die -with no known reason- are those that produce dopamine and proportionate dopaminergic innervation to the encephalon. In fact, almost all the symptoms exhibited by patients with the disease can be explained by the lack of dopamine in the substantia nigra.  
This area uses the neurotransmitter to communicate neurons from the base ganglia. Ganglia are responsible of modulating and modifying movements. 
The nigrostriatal system participates in planning and automatic execution of learned movements. When the ganglia activity decreases, so it does the amount and velocity of movements, something typical of the disease.   
 
 
        
             
        
        
        
Water diffusion is called osmosis. Oxygen is a small molecule and it's nonpolar, so it easily passes through a cell membrane. Carbon dioxide, the byproduct of cell respiration, is small enough to readily diffuse out of a cell. Small uncharged lipid molecules can pass through the lipid innards of the membrane.
        
             
        
        
        
CO2 is considered organic because it doesn’t contain a hydrogen. Organic compounds must contain carbon bound to hydrogen and possibly other elements.