1. The numbers and are respectively the additive and multiplicative identities of rational numbers

 0 and 1, in that order

The numbers   0   and   1   are respectively the additive and multiplicative identities of rational numbers.

Explanation:

The additive identity is 0 because adding 0 to any number leads to the original number. For instance, 7+0 = 7. In general we can say x+0 = x or we could also say 0+x = x.

The multiplicative identity is 1 because multiplying 1 with anything leads to that original number. Example: 1*5 = 5 or 9*1 = 1. The general template is x*1 = x which is the same as saying 1*x = x.

These ideas not only apply to rational numbers, but to real numbers as well.

answer: a and b

step-by-step explanation: