TASK DEFINITION: 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.
PROBLEM: Passage: Double fertilization refers to a process in which two sperm cells fertilize cells in the ovary. This process begins when a pollen grain adheres to the stigma of the pistil (female reproductive structure), germinates, and grows a long pollen tube. While this pollen tube is growing, a haploid generative cell travels down the tube behind the tube nucleus. The generative cell divides by mitosis to produce two haploid (n) sperm cells. As the pollen tube grows, it makes its way from the stigma, down the style and into the ovary. Here the pollen tube reaches the micropyle of the ovule and digests its way into one of the synergids, releasing its contents (which include the sperm cells). The synergid that the cells were released into degenerates and one sperm makes its way to fertilize the egg cell, producing a diploid (2n) zygote. The second sperm cell fuses with both central cell nuclei, producing a triploid (3n) cell. As the zygote develops into an embryo, the triploid cell develops into the endosperm, which serves as the embryo's food supply. The ovary now will develop into fruit and the ovule will develop into seed.

SOLUTION: When a pollen tube fertilizes cells in the ovary, what is it called?

PROBLEM: Passage: Paleoclimatologists measure the ratio of oxygen-18 and oxygen-16 in the shells and skeletons of marine organisms to determine what the climate was like millions of years ago (see oxygen isotope ratio cycle). Seawater molecules that contain the lighter isotope, oxygen-16, evaporate at a slightly faster rate than water molecules containing the 12% heavier oxygen-18; this disparity increases at lower temperatures. During periods of lower global temperatures, snow and rain from that evaporated water tends to be higher in oxygen-16, and the seawater left behind tends to be higher in oxygen-18. Marine organisms then incorporate more oxygen-18 into their skeletons and shells than they would in a warmer climate. Paleoclimatologists also directly measure this ratio in the water molecules of ice core samples that are up to several hundreds of thousands of years old.

SOLUTION: Who measures oxygen-18 and oxygen-16 in skeletons of all organisms?

PROBLEM: Passage: For 2016, U.S. News & World Report ranked BYU as tied for 66th for national universities in the United States. A 2013 Quarterly Journal of Economics study of where the nation's top high school students choose to enroll ranked BYU No. 21 in its peer-reviewed study. The Princeton Review has ranked BYU the best value for college in 2007, and its library is consistently ranked in the nation's top ten No. 1 in 2004 and No. 4 in 2007. BYU is also ranked No. 19 in the U.S. News and World Report's "Great Schools, Great Prices" lineup, and No. 12 in lowest student-incurred debt. Due in part to the school's emphasis on undergraduate research, in rankings for 2008-2009, BYU was ranked No. 10 nationally for the number of students who go on to earn PhDs, No. 1 nationally for students who go on to dental school, No. 6 nationally for students who go on to law school, and No. 10 nationally for students who go on to medical school. BYU is designated as a research university with high research activity by the Carnegie Foundation for the Advancement of Teaching.]] Forbes Magazine ranked it as the No. 1 "Top University to Work For in 2014" and as the best college in Utah.

SOLUTION:
Where did BYU rank in 2013 in the U.S. News & World Report rankings?