In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

Q: What can a tree produce after it is mature?, Context: Different pieces of wood cut from a large tree may differ decidedly, particularly if the tree is big and mature. In some trees, the wood laid on late in the life of a tree is softer, lighter, weaker, and more even-textured than that produced earlier, but in other trees, the reverse applies. This may or may not correspond to heartwood and sapwood. In a large log the sapwood, because of the time in the life of the tree when it was grown, may be inferior in hardness, strength, and toughness to equally sound heartwood from the same log. In a smaller tree, the reverse may be true.

A: wood
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Q: what field of study is mentioned second to last?, Context: Muslim physicians contributed to the field of medicine, including the subjects of anatomy and physiology: such as in the 15th century Persian work by Mansur ibn Muhammad ibn al-Faqih Ilyas entitled Tashrih al-badan (Anatomy of the body) which contained comprehensive diagrams of the body's structural, nervous and circulatory systems; or in the work of the Egyptian physician Ibn al-Nafis, who proposed the theory of pulmonary circulation. Avicenna's The Canon of Medicine remained an authoritative medical textbook in Europe until the 18th century. Abu al-Qasim al-Zahrawi (also known as Abulcasis) contributed to the discipline of medical surgery with his Kitab al-Tasrif ("Book of Concessions"), a medical encyclopedia which was later translated to Latin and used in European and Muslim medical schools for centuries. Other medical advancements came in the fields of pharmacology and pharmacy.

A: pharmacology
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Q: What class of drugs is used in execution?, Context: In the 2010s, American jurisdictions have experienced a shortage of lethal injection drugs, due to anti-death penalty advocacy and low production volume. Hospira, the only U.S. manufacturer of sodium thiopental, stopped making the drug in 2011. The European Union has outlawed the export of any product that could be used in an execution; this has prevented executioners from using EU-manufactured anesthetics like propofol which are needed for general medical purposes. Another alternative, pentobarbital, is also only manufactured in the European Union, which has caused the Danish producer to restrict distribution to U.S. government customers.

A:
anesthetics
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