Answer:
Explanation:
friction between two rock surfaces grinding away minerals.
 
        
                    
             
        
        
        
Answer:
Trophic level
Consumer
Producer
Explanation:
All living organisms require energy for their life processes, which they obtain by taken in food. In an ecosystem, this food is derived when organisms feed on each other. This process that eventually leads to a flow of energy within organisms is called FOOD CHAIN. 
A food chain or food web always begins with a unique set of organisms called PRODUCERS. Producers are autotrophs capable of harvesting light energy from the sun and use it to produce their food (chemical) in a process called PHOTOSYNTHESIS. Other organisms called HETEROTROPHS feed on these producers to derive energy. In ecology, they are called CONSUMERS. Other consumers feed on the previous ones also to get energy.
 Hence, each step of the food chain is occupied by organisms that obtain and store energy by feeding on another organism. This step is called TROPHIC LEVEL. 
In a nutshell, a PRODUCER (usually plants) starts the food chain/web due to its photosynthetic ability. This producer gets eaten by an organism called CONSUMER and in the process, the energy and nutrient stored in the producers flows to the consumer. Another consumers feeds on the previous one and the energy keeps flowing. Each step of the food chain occupied by an organism that stores and transfers this energy is called TROPHIC LEVEL.
 
        
             
        
        
        
I think this information may be help you
The plants in a specific environment be impacted if there was a sudden drop in the amount of bacteria present in that area, there are positive and negative consequences associated with this situation.
Positive:
The decrease in bacterial colonization will prevent the plant from the diseases caused by the bacteria and this will promote plant growth. Like, black rot in Brassica caused by Xanthomonas campestris, bacterial canker in tomato, capsicum and chilli caused by Clavibacter michiganesis. 
Negative:
Plants remains in symbiotic relationship with bacteria in order to obtain impermeable inorganic minerals from the soil. In the absence of bacteria, the plants will not receive these nutrients, and their growth may be hampered. Example bacteria fixes atmospheric nitrogen which is taken up by the root nodules of leguminous plants. In return these bacteria gets the food like carbohydrates produce by the plants
        
             
        
        
        
Nosocomial infection-acquired in hospital or health card facility