Several muscles cross the shoulder joint. What describes the actions of these muscles as you lift your arm at the shoulder joint?
a.
All of the muscles contract, but to different extents.
b.
All of the muscles contract equally.
c.
Some of the muscles contract, while other muscles relax.
d.
Some of the muscles contract, while other muscles detach from the bones.

Kelly ran electricity though a sample of water using electrolysis. the water changed into two gases, x and y. it was not possible to break down the gases x and y into simpler particles.

Approximately what portion of the foods that we eat have been genetically modified in some way? a.fewer than 10% b.about 50% c.nearly 100%

What is the main difference between the central nervous system (cns) and the peripheral nervous system (pns)? .the cns involves the brain and spinal cord, and the pns involves the body nerves. the cns involves the body nerves, and the pns involves the brain and spinal cord. the cns involves sensory neurons, and the pns involves motor neurons. the cns involves motor neurons, and the pns involves sensory neurons.