For what reason did the early Greeks believe the appropriate shape for an orbit was round? Select all that apply. Ptolemy proved that orbits were circular.
Greeks believed the circle represented perfection.
The circular orbit and epicycles allowed for relatively accurate predictions in the placement of the planets.
The earth was known to be round at this time.

Oxygen and nutrients are moved through the body by the: a. circulatory system c. lymphatic system b. digestive system d. reproductive system

Acylinder with a movable piston contains 11.7 moles of a monatomic ideal gas at a pressure of 1.32×10^5 pa. the gas is initially at a temperature of 300 k. an electric heater adds 43200 j of energy into the gas while the piston moves in such a way that the pressure remains constant. cp=20.79 j k^−1 mol^−1 for a monatomic ideal gas, and that the number of gas molecules is equal to avogadro's number (6.022×10^23) times the number of moles of the gas. (a) what is the temperature of the gas after the energy is added? (b) what is the change in volume of the gas? (c) how much work is done by the gas during this process?

Which accounts for an increase in the temperature of a gas that is kept a constant volume