In this task, you will be presented with a context passage, a question about that paragraph, and a possible answer to that question. The task is to check the validity of the answer. Answer with "Yes" or "No".

Ex Input:
The inhabited history of the Las Vegas Valley stretches to 23,000 b.c. , when much of the area was covered by a prehistoric lake. During this period, the indigenous people lived in caves, hunting the mammals that gathered at the shoreline. The landscape of the valley changed dramatically over the next 200 centuries. The glaciers feeding the lake melted away and the lake evaporated. Fossils tell an obscure story of man's slow and sporadic development. Around 3000 b.c. , native Archaic Indians began to develop a lasting hunting and gathering culture. By this time, the valley was in much the same geographic state as it exists in today, with one exceptionthe presence of artesian springs that bubbled to the surface in several areas. These springs fed a network of streams draining through the Las Vegas Wash to the Colorado River. The areas surrounding the springs were desert oases: sprawling collections of grasses, trees, and wildlife. Many springs lay in areas that would eventually become the center of the modern Las Vegas metropolis. For about 4000 years, the Archaics thrived in a culture that included many signs of early civilization. Signs of even more advancement appeared halfway through the first millennium a.d. , when the Anasazi Indians inhabited the valley. Far more progressive than the Archaics, the Anasazi utilized such formal agricultural techniques as irrigation to assist their harvest. This permitted the Anasazi to achieve a benchmark of advanced societythe ability to live in permanent shelters year-round without need to follow wildlife. Mysteriously, the Anasazi vanished from the valley around a.d. <sep>When did the Anasazi begin to inhabit the valley?<sep>1000 a.d

Ex Output:
No

Ex Input:
When you get sick, your body springs to action. Your body starts to fight the illness. Thats why you want to eat right and get plenty of sleep. You need a strong immune system to fight off illness. Plants dont have an immune system. That does not mean they do not get sick. Plants are affected by disease just like us. Typically, their first line of defense is the death of part of the plant. This prevents the infection from spreading. Many plants also produce special chemicals to fight disease. For example, willow trees produce a chemical to kill the bacteria. The same compound is used in many acne products. You can see a picture of a willow tree in Figure Plants may be smarter than we think. No, they cannot talk to each other. They may be able to send messages, though. <sep>What typically happens in a plant first to prevent an infection from spreading?<sep>Having some rest

Ex Output:
No

Ex Input:
A stranger in town meets pretty young Susan Martinez De La Cruz and accompanies her to a barbecue , where wealthy Jason Carberry is saying a few words for the recently departed Robin Randall , a citizen who got shot . Jason objects to the stranger's presence , being Susan's guardian and protective of her . He challenges him to a shootout , but the stranger pulls his pistol before Jason's can even clear the holster . Calaveras Kate , a saloon singer who's in love with Jason , is relieved when the stranger declines to pull the trigger . Rafael Moreno suddenly rides into town and picks a fight with the stranger . Their brawl continues until the arrival of Judge Wallace Wintrop and his niece , Sheila , who have come to town from back East and deplore all this random violence out West . The stranger is recognized as Reb Randall , the dead man's brother . He is looking for the killer , who could be Rafael , or could be Jason , or could even be Billy Buckett , the coward of the county . The women hold their breath to see if the men they love will survive . <sep>What did we learn about Jason?<sep>He might be the killer of Robin Randall

Ex Output:
Yes