Removing and adding to list?

Question

Unity

Am I understanding correctly or does it work differently?

When entering, I try to add an object to my list, and when I exit, remove it from there

void OnTriggerEnter2D(Collider2D collider)
    {
        if (collider.gameObject.tag == "Zombie")
        {
            zombieArray.Add(collider.gameObject);

        }
    }



 void OnTriggerExit2D(Collider2D collider)
    {
        zombieArray.Remove(collider.gameObject);

    }

He adds to add, but about deleting the question, will he delete the object that came out? and what will happen to the index, in case of deleting the value that was before? will it be equal to Null or just deleted?
Type, let's say 1,2.3,4, I delete the 2nd element, 1,3,4, remain?

Answer 1

Yes, it's just that there won't be a deleted object in the list, the rest will move.