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

Ex Input:
What needs consistency?, Context: The simplest valve gears give events of fixed length during the engine cycle and often make the engine rotate in only one direction. Most however have a reversing mechanism which additionally can provide means for saving steam as speed and momentum are gained by gradually "shortening the cutoff" or rather, shortening the admission event; this in turn proportionately lengthens the expansion period. However, as one and the same valve usually controls both steam flows, a short cutoff at admission adversely affects the exhaust and compression periods which should ideally always be kept fairly constant; if the exhaust event is too brief, the totality of the exhaust steam cannot evacuate the cylinder, choking it and giving excessive compression ("kick back").[citation needed]

Ex Output:
exhaust and compression periods

Ex Input:
What numeral standard was used in the Super Bowl 4 logo?, Context: On June 4, 2014, the NFL announced that the practice of branding Super Bowl games with Roman numerals, a practice established at Super Bowl V, would be temporarily suspended, and that the game would be named using Arabic numerals as Super Bowl 50 as opposed to Super Bowl L. The use of Roman numerals will be reinstated for Super Bowl LI. Jaime Weston, the league's vice president of brand and creative, explained that a primary reason for the change was the difficulty of designing an aesthetically pleasing logo with the letter "L" using the standardized logo template introduced at Super Bowl XLV. The logo also deviates from the template by featuring large numerals, colored in gold, behind the Vince Lombardi Trophy, instead of underneath and in silver as in the standard logo.

Ex Output:
Arabic

Ex Input:
What can each system do regarding the other?, Context: The root system and the shoot system are interdependent the usually nonphotosynthetic root system depends on the shoot system for food, and the usually photosynthetic shoot system depends on water and minerals from the root system. Cells in each system are capable of creating cells of the other and producing adventitious shoots or roots. Stolons and tubers are examples of shoots that can grow roots. Roots that spread out close to the surface, such as those of willows, can produce shoots and ultimately new plants. In the event that one of the systems is lost, the other can often regrow it. In fact it is possible to grow an entire plant from a single leaf, as is the case with Saintpaulia, or even a single cell which can dedifferentiate into a callus (a mass of unspecialised cells) that can grow into a new plant. In vascular plants, the xylem and phloem are the conductive tissues that transport resources between shoots and roots. Roots are often adapted to store food such as sugars or starch, as in sugar beets and carrots.

Ex Output:
regrow it