Answer:
An introduced species, alien species, exotic species, adventive species, immigrant species, ... Non-native species can have various effects on the local ecosystem. ... Some species have been introduced intentionally to combat pests
Explanation:
 
        
             
        
        
        
Answer:
A food chain is a representation of what eats what in an ecosystem.
A combination of food chains is termed as a food web.
Example of two food chains in a food web are :
Example No 1: 
Plant----- Grasshopper------ Frog---snake--- bacteria
Example No 2:
Plant---- rabbits---- fox---- bacteria
In a food chain, producers are usually plants and algae which are able to make their own food. Consumers feed on the plants. In example no 1, grasshoppers are primary consumers, frogs are secondary consumers, snakes are tertiary consumers.
In example no 2,plants are producers, rabbits are primary consumers and foxed are secondary consumers.
Decomposers are organisms that feed on the dead organisms in a food chain. In both the examples of food chain, bacteria are the decomposers. 
 
        
                    
             
        
        
        
14: Operons allow prokaryotes to replicate DNA at the appropriate time.
Operons are specific regions of genes that are linked to a singular process. They ensure that the expression of these genes does not go unchecked and only occurs when necessary. Two key examples of this in humans are the lac operon and trp operon. 
15. The central dogma of molecular biology is:
DNA to RNA to Proteins
Protein Synthesis occurs in 3 steps. 
First our DNA is translated into RNA. Next the RNA is sequenced into Amino Acids by reading the corresponding 3-Base Codons. These Amino Acid sequences form various protein structures.