(1) False. [tex]\{0\}\in\mathscr{U}[/tex] is saying "the set containing only 0 (that is, {0}) is an element of [tex]\mathscr U[/tex]", but this is not the case. [tex]\mathscr U[/tex] is the set containing only 0 and 1.
(2) True. [tex]\{0\}\subset\mathscr{U}[/tex] means "the set {0} is a subset of [tex]\mathscr{U}[/tex]". 0 itself is an element of [tex]\mathscr U[/tex], so {0} is indeed a subset of [tex]\mathscr U[/tex].
(3) True. 0 is clearly an element of [tex]\mathscr U[/tex].
(4) False. This statement says "0 is a subset of [tex]\mathscr U[/tex]" but 0 itself is not a set, it's a number.
