I think it is A but not 100% sure. Think of an enzyme like a key unlock the lock is the protein. And to activate getting inside your car or house you have to fit the key into the lock.
        
             
        
        
        
They'll have to do the following 2 stpes:
- Look for evidence that suports their conclusion
- Do tests in order to prove their hypothesis
Hope it helped,
BioTeacher101
 
        
                    
             
        
        
        
Answer:
D)  Sea otters are a keystone species as they prevent a herbivorous species from completely destroying a plant species.
Explanation:
 
        
             
        
        
        
The plant
cells vacuole is larger compared to the animals cells' because the plants
vacuoles takes up 90% of the cells volumes. Vacuole stores food for the
organism. In this case since, plants manufacture their own food, it is
necessary for it to have a large storage space or a large vacuole.
        
             
        
        
        
<h2>
Answer:</h2>
<u>Blood clotting</u> is a positive feedback.
<h2>
Explanation:</h2>
All the physiological process occurring in the body are monitored by two types of mechanism called negative feedback and positive feedback.  
Positive feedback is the reaction which occurs with the feedback from the actions the system has performed. The blood clot occurs with palette formation which is regulated with the blood lose (continuous feedback).
Negative feedback is a reaction that is the invert of the change distinguished, meaning it capacities to decrease the change. A change is recognized by a receptor and an effector is made to incite a contrary impact which facilitates further reaction.  
The physiological process such as shivering, sweating and digestion are examples of negative feedback.