a cylindrical wire initially has resistance r and length l. the wire is clamped in place at its midpoint, and the portion to the left of the clamp remains unchanged. the portion to the right of the clamp is stretched out to a length l.

The answer is that they are composed mostly of liquid water.

Answer;

hot magma rises and pushes up toward the lithosphere, and as it cools it cycles back down toward the core to be heated again.

explanation; convection currents are the circular pathways taken by a fluid that enhances heat transfer by the process known as convection which occurs in fluids.convection currents transfer heat from one place to another by mass motion of a fluid. earth mantle is in a semi-liquid state and behaves like any other fluid, rising up from the bottom of the mantle after becoming hotter and less dense from heat of the earth's core, as the rock loses heat into the earth's crust it becomes cooler and more dense, then sinking back down to the core, then repeating the cycle.

Diamonds or jewelry in the broader sense are other  veblen goods and so are high-end watches.