Let P(a, b) be a point on the coordinate plane. Then the following hold:
i) If a>0, b>0 then P is in the I.Quadrant.
ii) If a<0, b>0 then P is in the II.Quadrant.
iii) If a<0, b<0 then P is in the III.Quadrant.
iv) If a>0, b<0 then P is in the IV.Quadrant.
v) If a=0 and b is positive or negative, then P is on the y-axis.
vi) If b=0 and a is positive or negative, then P is on the x-axis.
Since we have: a=0, and 19 positive, then this point is on the y-axis.
Answer: y-axis