This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.

Q: Passage: Uranium is a naturally occurring element that can be found in low levels within all rock, soil, and water. Uranium is the 51st element in order of abundance in the Earth's crust. Uranium is also the highest-numbered element to be found naturally in significant quantities on Earth and is almost always found combined with other elements. Along with all elements having atomic weights higher than that of iron, it is only naturally formed in supernovae. The decay of uranium, thorium, and potassium-40 in the Earth's mantle is thought to be the main source of heat that keeps the outer core liquid and drives mantle convection, which in turn drives plate tectonics. Question: Where does uranium rank among elements in terms of its abundance in the Earth's crust?

A: 51st
****
Q: Passage: According to Sun Jiadong, the chief designer of the navigation system, "Many organizations have been using our system for a while, and they like it very much." Question: What did Sun Jiadong have to say about the BeiDou navigation system?

A: "Many organizations have been using our system for a while, and they like it very much."
****
Q: Passage: Congress often enacts statutes that grant broad rulemaking authority to federal agencies. Often, Congress is simply too gridlocked to draft detailed statutes that explain how the agency should react to every possible situation, or Congress believes the agency's technical specialists are best equipped to deal with particular fact situations as they arise. Therefore, federal agencies are authorized to promulgate regulations. Under the principle of Chevron deference, regulations normally carry the force of law as long as they are based on a reasonable interpretation of the relevant statutes. Question: Federal agencies are authorized to make what public?

A:
regulations
****