Over and over, the cycle of rock sinking and rising takes place due to convection currents in Earth. One full cycle takes millions of years. What forces drive the convection currents that cause this cycle to take place? Group of answer choices

heating from the crust and mantle

heating from the core and mantle

cooling from the crust and core

cooling from the core and mantle

An object weighs 40n in air, weighs 20n when submerged in water and 30n when submerged in a liquid of unknown density. what is the density of the liquid?

What was the first instrument to ever record an earthquake?

Two conductors, a and b, are each in the shape of a tetrahedron. but of different sizes. they are charged in the following manner: 1. tetrahedron a is charged from an electrostatic generator to charge q. 2. tetrahedron a is briefly touched to tetrahedron b. 3. steps 1 and 2 are repeated until the charge on tetrahedron b reaches a maximum value. if the charge on tetrahedron b was q/4 after the first time it touched tetrahedron a. what is the final charge qbmax on tetrahedron b?