Path Of A Plane

Riddle: I'm rough to the touch; Blood does me through veins; I can be taken in math; The path of a plane. What am I?

Answer: Coarse/Course

Source: https://www.riddles.com/index.php/2038

I'm rough to the touch;
Blood does me through veins;
I can be taken in math;
The path of a plane.
What am I? — Path of a plane by Morgan Foster v1.

Riddle: I'm rough to the touch;
Blood does me through veins;
I can be taken in math;
The path of a plane.
What am I? Answer: Coarse/Course — by Morgan Foster v2.