To get the best possible answer. (sorry if im wrong)
Your answer will be Radio Waves .
That seems to be the only to make sense. Hope that helps u
Answer:
Gravitational force is <u>noncontact</u> force
Explanation:
Contact force occurs due to the contact between two different objects. Non-contact force occurs due to either attraction or repulsion between two objects such that there is no contact between these objects. There is no field linked with the contact force. ... Gravitational force is an example of a non-contact force.
Respiratory and circulatory
Here refrigerator removes 55 kcal heat from freezer
Refrigerator releases 73.5 kcal heat to surrounding
So here we can use energy conservation principle by II Law of thermodynamics
the law says that

here we know that
= heat released to the surrounding
= heat absorbed from freezer
W = work done by the compressor
now using above equation we can write



So here compressor has to do 18.5 k cal work on it