Jennifer and katie are leaning on each other. jennifer weighs 150 and katie weighs 120. which one is pushing harder on the other?

They're just standing there, not going anywhere. Definitely not accelerating. That tells us that the net force on each one must be zero. So whatever push Katie is giving, she must be getting one the same size from Jennifer. And the same goes for the other lady.

What ever push she's giving her friend, her friend is also giving her.

Somehow, they're both pushing with equal forces.

layer a is the exosphere and layer b is the thermosphere.   is the answer i think but i hope this .

a

explanation:

no diagram was provided, but i'm guessing it's the one i've attached to my answer.

here, a mechanical force turns the rod.   this generates an electric current in the coil, which powers the bulb.