are filled with special absorbing elements that move up and down between the uranium rods to keep the atoms from getting out of control.

The correct answer is - control rods.

Explanation:

Control rods are filled with special absorbing agents such as boron, cadmium, silver, and others to absorb as many neutrons as to control the fission reaction by moving them up and down in between uranium rods.

These control rods are used to prevent the nuclear reaction from getting out of control in the nuclear plant or reactor by absorbing the neutrons and prevent uranium to convert.

lithosphere and asthenosphere

- "the choice that is not an indicator of a chemical change is "state of matter changes". more common than not, chemical reactions produce energy in the form of light or heat. along with energy, they also produce a new substance called the product that could be in any state of matter (solid, gas, or liquid)."