What are linear data structures?

#Crearting a Node
class Node:
    def _init_(self,data):
        self.data=data
        self.ref=None
# Creating Linked List
class LinkedList:
    def _init_(self):
        self.head=None
# printing or traversal Operation
    def Traversal(self):
        if self.head is None:# self.head==None
            print("Linked List is Empty!!!")
        else:
            h=self.head
            while h is not None:
                print(h.data,"----->")
                h=h.ref

# Stack implementation using List
stack=[]
def push():
    if len(stack)==size: # check wether the stack is full or not
        print("Stack is Full!!!!")
    else:
        element=input("Enter the element:")
        stack.append(element)
        print(stack)
def pop_element():
    if not stack:# or if len(stack)==0
        print("Stack is Empty!!!")
    else:
        e=stack.pop()
        print("element removed!!:",e)
        print(stack)
def display():
    print(stack)
    size=int(input("Enter the size of Stack:"))
    while True:
        print("Select the Operation:\n 1.Push \n 2.Pop \n 3. Display \n 4. Quit")
        ch=int(input())
        if ch==1:
            push()
        elif ch==2:
            pop_element()
        elif ch==3:
            display()
        elif ch==4:
            break
        else:
            print("Invalid Option!!!")

# implementing Queue using List :
from collections import deque
q=deque()
q.append(10)
q.append(100)
q.append(1000)
q.append(10000)
print("Initial Queue is:",q)
print(q.popleft())
print(q.popleft())
print("After Removing elements:",q)