Paratism is the practice of living as a parasite in or on another organism. Mutualism is the way two organisms of different species exist in which each individual benefits from the activity of the other.
        
             
        
        
        
Answer:
<u>All the substrates are bound to the enzyme</u>, thats why the reaction rate stopped increasing.
Explanation:
Actually an enzyme works by binding a substrate molecule to its active site, producing a product  , resulting in an increase in the rate of reaction.
             Enzyme + substrate = Enzyme + product
Whenever enzymes are added , reaction rate increases as the substrates are being bound to the enzyme's active sites but then occurs a stage where further addition of enzyme cannot increase the reaction rate because all the substrates have bound to the enzyme and <u>there are no substrates left.</u> Hence the reaction rate stopped increasing.