Why are nylon ropes used in rock climbing?
a.
nylon ropes are very stiff and therefore shorten the period of time over which a climber's fall is broken.
c.
there is no physical reason for the nylon material, it is just cheaper.
b.
nylon ropes can easily stretch and therefore extends the period of time over which a climber's fall is broken.
d.
none of the above.

the order for strong to weak forces such as

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force

the fundamental forces are those forces that act between to objects or element to make interactions. there are four types of fundamental forces such as strong and weak nuclear forces (due to protons and electrons), electromagnetic force (due to the motion of electrons) and gravitational force (due to orbital movement of the planet). if these forces are arranged on the basis of their maximum strength then the order is

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force

3. dark matter

empty space could also be a simple vacuum