instruction:
This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.
question:
Passage: Glass has the ability to refract, reflect, and transmit light following geometrical optics, without scattering it. It is used in the manufacture of lenses and windows. Common glass has a refraction index around 1.5. This may be modified by adding low-density materials such as boron, which lowers the index of refraction (see crown glass), or increased (to as much as 1.8) with high-density materials such as (classically) lead oxide (see flint glass and lead glass), or in modern uses, less toxic oxides of zirconium, titanium, or barium. These high-index glasses (inaccurately known as "crystal" when used in glass vessels) cause more chromatic dispersion of light, and are prized for their diamond-like optical properties.
answer:
What can be used to make glass less dense?

question:
Passage: There are many names for God, and different names are attached to different cultural ideas about God's identity and attributes. In the ancient Egyptian era of Atenism, possibly the earliest recorded monotheistic religion, this deity was called Aten, premised on being the one "true" Supreme Being and Creator of the Universe. In the Hebrew Bible and Judaism, "He Who Is", "I Am that I Am", and the tetragrammaton YHWH are used as names of God, while Yahweh and Jehovah are sometimes used in Christianity as vocalizations of YHWH. In the Christian doctrine of the Trinity, God, consubstantial in three persons, is called the Father, the Son, and the Holy Spirit. In Judaism, it is common to refer to God by the titular names Elohim or Adonai, the latter of which is believed by some scholars to descend from the Egyptian Aten. In Islam, the name Allah, "Al-El", or "Al-Elah" ("the God") is used, while Muslims also have a multitude of titular names for God. In Hinduism, Brahman is often considered a monistic deity. Other religions have names for God, for instance, Baha in the Baha'i Faith, Waheguru in Sikhism, and Ahura Mazda in Zoroastrianism.
answer:
In the Egyptian era of Atenism, what were YHWH and I am that I am used as?

question:
Passage: The 5th Dalai Lama is known for unifying the Tibetan heartland under the control of the Gelug school of Tibetan Buddhism, after defeating the rival Kagyu and Jonang sects and the secular ruler, the Tsangpa prince, in a prolonged civil war. His efforts were successful in part because of aid from Gushi Khan, the Oirat leader of the Khoshut Khanate. With Gushi Khan as a largely uninvolved overlord, the 5th Dalai Lama and his intimates established a civil administration which is referred to by historians as the Lhasa state. This Tibetan regime or government is also referred to as the Ganden Phodrang.
answer:
Who is known for unifying the Tibetan heartland under the control of Kagyu?