In arrays, an index is used to access an element. Elements in the array are organized in sequential order, which makes it easy to access and modify elements if an index is used. Array also has a fixed size. Elements are allocated at the time of its creation. In linked list, a pointer is used to access an element. Elements of a linked list are not necessarily stored in sequential order. A linked list has an unknown size because it can contain nodes at the time of its creation. A pointer is used to access an element, so memory allocation is easier.