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

Passage: The way a mineral cleaves or fractures depends on the crystal structure of the mineral. Answer: the crystal structure
The way a mineral cleaves or fractures depends on what part of the mineral?

Passage: Diagram of a typical prokaryotic cell. Among other things, prokaryotic cells have a plasma membrane, cytoplasm, ribosomes, and DNA. Prokaryotes do not have membrane-bound organelles or a cell nucleus. Answer: not membrane-bound
What are unique about prokaryotic cells' organelles?

Passage: In the previous lesson, we discussed pure substances and mixtures. We indicated that the components of a mixture could be separated by physical means, but the components of a pure substance could not. Pure substances can only be broken down further through chemical means. In this lesson, we list several methods for separating mixtures. We will also be looking at chemical changes which alter the chemical identity of a substance, and how to recognize when a chemical change is taking place. Answer: chemical
While components of a mixture can be separated by physical means, the components of a pure substance can only be broken down through what means?