1)which statement best describes energy in an open system?

a) all energy and matter are contained within the system.

b) energy and matter flow into and out of the system.

c) matter flows into and out of the system; energy does not.

d) there is no energy in an open system; there is matter.

2)when a sound source is moving toward the observer, the observer will hear a

a) higher pitch due to the change to a lower frequency.

b) higher pitch due to the change to a higher frequency.

c) lower pitch due to the change to a higher frequency.

d) lower pitch due to the change to a lower frequency.