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

[Q]: Passage: Momentum is a vector quantity that has the same direction as the velocity of the object. Answer: object ' s velocity
[A]: Momentum is a vector quantity that has the same direction as what?

[Q]: Passage: Gases are also capable of dissolving in liquids. There are many examples of this in our everyday lives. For example, carbonated beverages contain dissolved carbon dioxide. We notice this when bubbles come out of solution when the beverage is opened. Another example is when oxygen from the air we breathe dissolves in our blood, where it is transported throughout the body. Fish and other aquatic organisms use gills to capture dissolved oxygen from their environments. Answer: oxygen
[A]: Fish and other aquatic organisms use gills to capture dissolved what?

[Q]: Passage: When iron filings and sulfur powder are mixed together in any ratio, they form a mixture. No chemical reaction occurs, and both elements retain their individual properties. A magnet can be used to mechanically separate the two elements by attracting the iron filings out of the mixture and leaving the sulfur behind. Answer: magnet
[A]:
What can be used to mechanically separate the two elements by attracting the iron filings out of the mixture and leaving the sulfur behind?