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.

Ex Input:
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?

Ex Output:
51st

Ex Input:
Passage: Tito's notable grandchildren include Aleksandra Broz, a prominent theatre director in Croatia; Svetlana Broz, a cardiologist and writer in Bosnia-Herzegovina; and Josip "Joska" Broz, Edvard Broz and Natali Klasevski, an artisan of Bosnia-Herzegovina. Question: Which of Tito's grandchildren is a cardiologist and writer?

Ex Output:
Svetlana Broz

Ex Input:
Passage: The first use of asphalt/bitumen in the New World was by indigenous peoples. On the west coast, as early as the 13th century, the Tongva, Luiseno and Chumash peoples collected the naturally occurring asphalt/bitumen that seeped to the surface above underlying petroleum deposits. All three used the substance as an adhesive. It is found on many different artifacts of tools and ceremonial items. For example, it was used on rattles to adhere gourds or turtle shells to rattle handles. It was also used in decorations. Small round shell beads were often set in asphaltum to provide decorations. It was used as a sealant on baskets to make them watertight for carrying water. Asphaltum was used also to seal the planks on ocean-going canoes. Question: What would early users of asphalt want to achieve by putting it on baskets?

Ex Output:
watertight