11. Fill in the blanks: (i) Zero has ____________ reciprocal. (ii) The numbers ___________ and __________ are their own reciprocals. (iii) The reciprocal of -5 is _____________. (iv) Reciprocal of 1/x where x is not equal to 0 is _____________. (v) The product of two rational numbers is always a ____________. (vi) The reciprocal of a positive rational number is _______________.