Multiple response: newton's second law (select 3)
a. one object exerts a force on another object.
b. changes the motion of an object
c. acting on a single object.
d. object exerts a force that is equal in size and opposite in direction back.
e. acting on two different objects
i know a is one of the answers..but i'm confused on what the other 2 are.

Air enters a gas turbine with two stages of compression and two stages of expansion at 100 kpa and 17°c. this system uses a regenerator as well as reheating and intercooling – the intercooler returns the air to the inlet temperature. the pressure ratio across each compressor is 4 ; 300 kj/kg of heat are added to the air in each combustion chamber; and the regenerator operates perfectly while increasing the temperature of the cold air by 20°c. determine the system’s thermal efficiency. assume isentropic operations for all compressor and the turbine stages and use constant specific heats at room temperature. (0.378)