What is the code? Please help!

Aline on the wall and a line on the floor are skew. always, sometimes, or never?

Which statement is true about a number and its additive inverse? a. their product is always one. b. their sum is always one. c. they are always reciprocals of each other. d. their sum is always zero.

Which of the following circles have their centers on the x-axis? check all that apply.