Which layer of the earth can only be studied by indirect means

The crust is the only one because it is the layer we are in and the other layers are so deep

Everything except for the crust, including the Mantle and the core.

6because i no yea yea

Firstly, the water in the dams hold gravitational potential energy as they are above ground level. the gravitational potential energy is then transferred to kinetic energy as it falls, spinning the turbinethe turbine then spins the generator, which is a large magnet surrounded by metal coils. by doing this, the generator generates electricity. in this action, the energy transfer taken place is kinetic to electric energy