Given a scientific passage and an answer, generate a question for the given answer.
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Question: Passage: There are no forces of attraction or repulsion between gas particles . Attractive forces are responsible for particles of a real gas condensing together to form a liquid. It is assumed that the particles of an ideal gas have no such attractive forces. The motion of each particle is completely independent of the motion of all other particles. Answer: superscripts

Answer: Which measure indicates the number of electrons in a given sublevel?

Question: Passage: Tuberculosis (TB) is a common and often deadly disease caused by a genus of bacterium called Mycobacterium . Tuberculosis most commonly attacks the lungs but can also affect other parts of the body. TB is a chronic disease, but most people who become infected do not develop the full disease. Symptoms include a cough, which usually contains mucus and coughing up blood. Answer: mycobacterium

Answer: What type of bacteria causes the disease called tuberculosis?

Question: Passage: Two unique properties of liquids are surface tension and viscosity. Surface tension is a force that pulls particles at the exposed surface of a liquid toward other liquid particles. Surface tension explains why water forms droplets, like the water droplet that has formed on the leaky faucet pictured in the Figure below . You can learn more about surface tension at this URL: http://io9. com/5668221/an-experiment-with-soap-water-pepper-and-surface-tension . Answer: surface tension

Answer:
What is the force that pulls particles at the exposed surface of a liquid toward other liquid particles called?