2 - Human refuse to stop polluting.
All other three are attempting to attack the problem of pollution.
        
             
        
        
        
Answer:
Lymphatic system
Explanation:
The lymphatic system helps maintain fluid balance in the body by collecting excess fluid and particulate matter from tissues and depositing them in the bloodstream.
 
        
             
        
        
        
Answer:
As image is not provided,let's discuss about ecological succession.
Explanation:
Ecological succession can be described as the development of a community from its pioneer to climax community. There are two types of ecological succession:
Primary ecological succession: This type of succession occurs in lands where there was no life before or in lands where signs of life have completely been removed like an lava eruption. The rocks in this land are broken down and slowly, pioneer species begin to grow.
Secondary  Succession: This type of succession arises after a natural disaster like fire etc or after any human activity has wiped out the previous community which survived on this land. smalls shrubs and grass starts to grow back on this land, which is replaced by the intermediate species and finally with the climax community.