Given a scientific passage and an answer, generate a question for the given answer.

Example Input: Passage: From a human point of view, natural resources can be classified as either renewable or nonrenewable. Answer: renewable or nonrenewable
Example Output: How can natural resources be classified from a human point of view?

Example Input: Passage: The nucleus is an example of an organelle . An organelle is any structure inside a cell that is enclosed by a membrane. Eukaryotic cells may contain many different organelles. Each does a special job. For example, the mitochondrion is an organelle that provides energy to the cell. You can see a mitochondrion and several other organelles in the animal cell in Figure above . Organelles allow eukaryotic cells to carry out more functions than prokaryotic cells can. Answer: an organelle
Example Output: Any structure inside a cell that is enclosed by a membrane is called?

Example Input: Passage: Clastic sedimentary rocks are grouped by the size of the sediment they contain. Conglomerate and breccia are made of individual stones that have been cemented together. In conglomerate, the stones are rounded. In breccia, the stones are angular. Sandstone is made of sand-sized particles. Siltstone is made of smaller particles. Silt is smaller than sand but larger than clay. Shale has the smallest grain size. Shale is made mostly of clay-sized particles and hardened mud. Answer: size of sediment
Example Output:
How are classic sedimentary rocks group?