Explanation:
Acid rain can cause serious problems for many different animals and plants. As a result, the entire food web is affected. For example, acid rain can cause phytoplankton in lakes to die. Insects, which rely on phytoplankton for food, now have less food to eat, and they begin to die as a result.
 
        
                    
             
        
        
        
Answer:
The following code is in python.
import statistics as st #importing statistics which include mean function.
def average(lst):  #function average.
    return st.mean(lst)#returning mean.
lst=a = list(map(int,input("\nEnter the list : ").strip().split()))#taking input of the list..
print("The average is "+str(average(lst)))#printing the average.
Output:-
Enter the list : 
1 2 3 4 5 6
The average is 3.5
Explanation:
I have used the statistics library which includes the mean function that calculates the mean or average of the list.In the function average having lst as an argument returns the mean of the list lst.
Then taking lst input from the user and printing it's average.
 
        
             
        
        
        
Answer:
C) 
Explanation:
One principle that can improve the efficiency of I/O would be to move processing primitives into hardware. Primitives are a semantic value representing something else such as words or numbers within the programming language. By moving them into hardware they system is able to read them at a much faster speed making the I/O more efficient.
 
        
                    
             
        
        
        
A mean is another word for average (kind of)
        
             
        
        
        
 Answer: B)  Pseudocode should be properly formatted.
Explanation:
  Pseudocode is defined as in the informal description of the given sequence, there is no need that it should be formatted properly. There is no such restriction required in the pseudocode as they are read by the humans not by the computer programs. 
Pseudocode should be terminating, executable and unambiguous and it uses structural convention of the programming language rather than using machine reading.