I need help with this question from my Theory of Algorithms course.

11] True or false: (a) The class of recursive languages is closed under infinite union. (b) All context-free languages are r.e. (c) Some r.e. languages are context-free. (d) If Church's thesis is false then there must be some algorithm which cannot be carried out by a Turing machine. (e) There is a Turing machine which can determine, for any two regular languages given in standard form, if they are equal. () The halting problem is the problem of determining if a universal Turing machine always halts from blank tape. (g) Right-linear grammars cannot be ambiguous