Answer:
Enzymes speed up a chemical reaction making the reaction easier to occur. 
 
        
             
        
        
        
A sex cell that hasn't been fertilized and has left the ovary would come out during the menstrual cycle under normal circumstances.
        
             
        
        
        
That would be death if you are referring to the human growth cycle
        
                    
             
        
        
        
Answer:
The correct answer is option - a surface protein allowing the pathogen to bind to host cells
Explanation:
Virulence factors are substances or molecules released by pathogens such as bacteria, fungi, viruses and protozoa that enhance their function effectiveness and enable them to get the following-
Attachment to host cell and surface.
Evasion of the immune response of the host.
Suppression or inhibition of the immune response  of host.
Getting nutrition from the host cells
Thus, the correct answer is option - a surface protein allowing the pathogen to bind to host cells.
 
        
             
        
        
        
Answer: Primary and secondary succession
Explanation: In primary succession, newly exposed or newly formed rock is colonized by living things for the first time. In secondary succession, an area previously occupied by living things is disturbed—disrupted—then recolonized following the disturbance.