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: Melatonin is absent from the system or undetectably low during daytime. Its onset in dim light, dim-light melatonin onset (DLMO), at roughly 21:00 (9 p.m.) can be measured in the blood or the saliva. Its major metabolite can also be measured in morning urine. Both DLMO and the midpoint (in time) of the presence of the hormone in the blood or saliva have been used as circadian markers. However, newer research indicates that the melatonin offset may be the more reliable marker. Benloucif et al. found that melatonin phase markers were more stable and more highly correlated with the timing of sleep than the core temperature minimum. They found that both sleep offset and melatonin offset are more strongly correlated with phase markers than the onset of sleep. In addition, the declining phase of the melatonin levels is more reliable and stable than the termination of melatonin synthesis.

Answer: When is Meletonin found in the system?

Question: Passage: The Cadet Organizations Administration and Training Service (COATS) consists of officers and non-commissioned members who conduct training, safety, supervision and administration of nearly 60,000 cadets aged 12 to 18 years in the Canadian Cadet Movement. The majority of members in COATS are officers of the Cadet Instructors Cadre (CIC) branch of the CAF. Members of the Reserve Force Sub-Component COATS who are not employed part-time (Class A) or full-time (Class B) may be held on the "Cadet Instructor Supplementary Staff List" (CISS List) in anticipation of employment in the same manner as other reservists are held as members of the Supplementary Reserve.

Answer: Who conducts formation of the cadets?

Question: Passage: Relations between the Rus' and Byzantines became more complex after Oleg took control over Kiev, reflecting commercial, cultural, and military concerns. The wealth and income of the Rus' depended heavily upon trade with Byzantium. Constantine Porphyrogenitus described the annual course of the princes of Kiev, collecting tribute from client tribes, assembling the product into a flotilla of hundreds of boats, conducting them down the Dnieper to the Black Sea, and sailing to the estuary of the Dniester, the Danube delta, and on to Constantinople. On their return trip they would carry silk fabrics, spices, wine, and fruit. The importance of this trade relationship led to military action when disputes arose. The Primary Chronicle reports that the Rus' attacked Constantinople again in 907, probably to secure trade access. The Chronicle glorifies the military prowess and shrewdness of Oleg, an account imbued with legendary detail. Byzantine sources do not mention the attack, but a pair of treaties in 907 and 911 set forth a trade agreement with the Rus', the terms suggesting pressure on the Byzantines, who granted the Rus' quarters and supplies for their merchants and tax-free trading privileges in Constantinople.

Answer:
What was not depended upon for the wealth and income of Rus?