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

[EX Q]: Passage: By losing an electron, the sodium atom becomes a sodium ion. It now has one less electron than protons, giving it a charge of +1. Positive ions such as sodium are given the same name as the element. The chemical symbol has a plus sign to distinguish the ion from an atom of the element. The symbol for a sodium ion is Na + . Answer: becomes sodium ion
[EX A]: What happens when a sodium atom loses an electron?

[EX Q]: Passage: In many ways, humans are unique among mammals. For example, we have bigger brains and a greater ability to learn than any other species in the mammalian class. In many ways, however, we are typical of the mammalian order to which we belong. That order is the Primate Order. To fully understand what it means to be human, you need to know more about this fascinating order of mammals. Answer: humans
[EX A]: What mammalian class has the greatest ability to learn?

[EX Q]: Passage: Chemical reactions vary widely in the speeds with which they occur. Some reactions occur very quickly. If a lighted match is brought in contact with lighter fluid or another flammable liquid, it erupts into flame instantly and burns fast. Other reactions occur very slowly. A container of milk in the refrigerator will be good to drink for weeks before it begins to turn sour. Millions of years were required for dead plants under Earth's surface to accumulate and eventually turn into fossil fuels such as coal and oil. Answer: speed
[EX A]:
Exemplified by a lit match bursting into flame or the process that forms fossil fuels, chemical reactions vary greatly in terms of what?