In this task, you are given a paragraph, and your task is to construct a question from the given passage. Construct question in such a way that (i) it is well explained in the paragraph, (ii) the words may/may not be present in the paragraph, (iii) it should start with what/how/describe. Avoid creating a question that (i) is just relevant to one or two sentences, and (ii) not relevant to passage. 

Input: Consider Input: Algae and plankton die. The dead algae and plankton end up part of sediment on a seafloor. The sediment breaks down. The bottom layers of sediment become compacted by pressure. Higher pressure causes the sediment to heat up. The heat causes chemical processes. The material becomes a liquid. Is known as oil. Oil moves up through rock. 

Output: How does oil form?


Input: Consider Input: Chemical reactions break down the bonds holding the rocks together. The rocks fall apart. They form smaller and smaller pieces. Oxidation takes place when oxygen combines with other elements in rocks. They form new types of rocks. The new substance is softer. Carbonation takes place when carbon dioxide reactions with certain types of rocks. A solution is formed that can easily be carried away by water. 

Output: What happens during chemical weathering?


Input: Consider Input: The liver takes in blood from the rest of the body. The liver uses enzymes to clean the blood. The cleaned blood is expelled. The liver creates bile from the items filtered. The liver takes energy and stores it as glycogen. The bile is sent to the intestines. 


Output: Describe how the liver works