Can identify which of the structure is in the code, and explain why it is used so... thank you

1.) Sequential Structures

2.) Decision Structures

3.) Repetition Structures

4.) String Methods

5.) Text File Manipulation

6.) Lists and Dictionaries

7.) Functions

8.) Program Modularization

import numpy px_terms = int(input('Enter number of terms in px: ')) qx_terms = int(input('Enter number of terms in qx: ')) poly = {} for i in range(px_terms): ele = int(input('Enter coefficient {} for px: '.format(i + 1))) # if 'px' is not present already, add empty list with 'px' as key if 'px' not in poly: poly['px'] = [] # after adding empty list with 'px' as key, append input to the list # I added this line because it also add 1st coefficient to the list. poly['px'].append(ele) # else, append input to the list else: poly['px'].append(ele) for i in range(qx_terms): ele = int(input('enter coefficient {} for qx: '.format(i + 1))) # if 'qx' is not present already, add empty list with 'qx' as key if 'qx' not in poly: poly['qx'] = [] # after adding empty list with 'qx' as key, append input to the list. # I added this line because it also add 1st coefficient to the list. poly['qx'].append(ele) # else, append input to the list else: poly['qx'].append(ele) option = input('Select Addition, Subtraction, Multiplication, Division: ') if option.lower() == "addition": print(numpy.polynomial.polynomial.polyadd(poly['px'], poly['qx'])) if option.lower() == "subtraction": print(numpy.polynomial.polynomial.polysub(poly['px'], poly['qx'])) if option.lower() == "multiplication": total = 0 for i in range(px_terms): ans = poly['px'][i] * poly['qx'][i] print(f"answer{i+1} = ", ans) total += ans print(f"total = {total}") if option.lower() == "division": qu, re = numpy.polynomial.polynomial.polydiv(poly['px'], poly['qx']) print("Quotient: ", qu) print("Remainder: ", re)