The effect of electricity on human body is determined not by the voltage but by the current that flows through our body (which is why it is safe to touch a van de Graaff generator at 100,000 volts but not safe to stick your finger into a 110-volt wall socket). Match each level of electrical current with the effect of the electrical current on our body.
Hint
1 mA
5 mA
10 mA
50 mA
100 mA
a. maximum harmless current
b. threshold of sensation
c. onset of pain
d. cannot let go for the duration of shock because of muscle contraction
e. heart rhythm may be disrupted; often fatal
Having said this, higher voltage does allow more current to be pushed through our body, according to Ohm's Law. So what makes a high-voltage van de Graaff generator safe to touch is the fact that it has a very low current limit (it quickly discharges on touch and does not maintain its high voltage), not that it has a high-voltage.