Answer:
HE IMPROVED THE WORLD BY GIVING SOMTHING THAT IT DID NOT HAVVE 
Explanation:
ENJOY :)
 
        
             
        
        
        
The answer is D, algae.
—Evidence—
•] Protozoan definition: a single-celled microscopic animal of a group of phyla of the kingdom Protista, such as an amoeba, flagellate, ciliate, or sporozoan.
•] it does not feature algae, therefore it’s D.
        
             
        
        
        
Not sure about the answer but I think its the size of the system
        
                    
             
        
        
        
<span>The basic building blocks of a cell membrane are phospholipids. Phospholipids contain a hydrophobic (insoluble in water) end made up of two fatty acid chains of nonpolar molecules such as carbons and hydrogens. The other end is hydrophobic (soluble in water) and contains polar phosphate molecules. These phospholipids are arranged in a bilayer with their hydrophilic end group exposed to water on each side of the membrane and the hydrophobic nonpolar molecules protected inside the double layer. </span>
        
             
        
        
        
Answer: A. Carbon dioxide is a product.
Explanation: During cellular respiration the body takes in oxygen and uses it and turns it into carbon dioxide and lets it out, thus carbon dioxide is a product.