Which one of the following choices is an effective way to pervent low-back pain
a. eliminate warm-up before exercise
b. lift objects by putting weight on your upper back
c. maintain correct posture
do. limit the amount of exercise you do per week

not too sure thinking it will always be directed towards the centre of the earth. could be wrong not sure

battery with hi vtge high val resist in series

if the person is shown to have +90n, then ans is -10n.

if the person is shown to have -90n, then ans is +10n.