Q1

let b1 = [11,13,13,11]
let s1 = new Set()
for (let x of b1) s1.add(x)
b1.length == 4,  s1.size == 2
Repetitions are removed

Q2

URL

let k = t.split('\n').length

Q3

Q4

nw  Point
se.x  Number
se.toString  Function
se.y.toString()  String

Q5

p2 is Object
p is Point 
with toString method

Q6

<div>
<b>Final</b> exam
<p>is easy</p>
</div>

Final exam

is easy