The source of the centripetal force that arises when a runner rounds a curve on a track is
tension
friction
weight
gravity

It's actually Friction.

I just did the test and got it right.

while taking a turn on a track, the track provides the frictional force acting towards the center of the curve. we know that to move in a curve, centripetal force is required. here since the frictional force acts towards the center, it provides the necessary centripetal force to move in circle. hence the correct choice is

friction

answer :

b

explanation:

a.metals can become magnetic if they have many spinning electrons that create magnetic fields.d.only some metals are attracted by magnets; these metals are called ferromagnetic.

d.wrapping an insulated wire around a metal with ferromagnetic properties and applying an electric current.