Which of the following is the empty set?
W = {x:x is a point common to two skew lines}

Which of the following is an empty set?

Which of the following are examples of the null set :- { y :y is a point common to any two parallel lines}

Whether the following is empty (null) set? {x:x is common point of any two parallel lines}.

Whether the following is empty (null) set? {x:x 7, x in N}

Whether the following is empty (null) set? { x: 5 < x < 6 ,x in N }

Whether the following is empty (null) set? { x:x^2 =25 and x is an odd integer}

Whether the following is empty (null) set? { x:x^2-2= 0 and x is rational}

Whether the following is empty (null) set? { x :x^2 =25 and x is an even integer}.

Which of the following are examples of the null set :- { x : x is a natural numbers, x 7 }

Which of the following pairs of sets are disjoint:- {x : x is an even integer } and {x : x is an odd integer}