Brad, Texas (CNN) -- Authorities were working on plans Friday for residents who were forced to flee a wildfire in northern Texas to return home, a day after firefighters made progress battling the blaze that destroyed dozens of homes. The blaze in Palo Pinto County scorched 6,200 acres by Thursday, according to the Texas Forest Service. The fire is burning near the resort of Possum Kingdom Lake, near the town of Brad, about 100 miles west of Dallas. "We feel much better about this fire today," as the blaze is now 50% contained, said John Nichols, a spokesman for the Forest Service. He said evacuations were lifted for some residents forced to evacuate the fire, which was driven by high temperatures and dry winds. The wildfire has destroyed 40 homes and nine RVs since it began Tuesday, the Forest Service said Thursday. Firefighters were receiving support from aerial tankers and helicopters. Authorities are mapping out plans to allow residents to return to their homes, said Palo Pinto County Sheriff Ira Mercer. Authorities also are trying to open the lake for the Labor Day holiday, he said. On Wednesday, evacuations were ordered in several communities on the north side of the lake after the fire charged over a ridge and approached a dam on the lake, CNN affiliate WFAA reported. The wildfire was moving so fast that the Forest Service pulled out of its command observation post, telling journalists and onlookers to get out of the way of the fire. "My house is right through here, though it may be gone," Tom Hardeston told WFAA as he watched the fire. Nearby ranchers battled to save their herds from the encroaching fire. "I'm just moving them from pasture to pasture," Cindi McCoy told WFAA, referring to her livestock. "As one pasture burns, I'm moving them back to that one and bring(ing) them back around."

Question: "Why was Cindi McCoy moving her livestock?"

OPTIONS:
- no
- yes

Answer: "To keep them safe."

Response: yes

General relativity includes a dynamical spacetime, so it is difficult to see how to identify the conserved energy and momentum. Noether's theorem allows these quantities to be determined from a Lagrangian with translation invariance, but general covariance makes translation invariance into something of a gauge symmetry. The energy and momentum derived within general relativity by Noether's presecriptions do not make a real tensor for this reason. Einstein argued that this is true for fundamental reasons, because the gravitational field could be made to vanish by a choice of coordinates. He maintained that the non-covariant energy momentum pseudotensor was in fact the best description of the energy momentum distribution in a gravitational field. This approach has been echoed by Lev Landau and Evgeny Lifshitz, and others, and has become standard. The use of non-covariant objects like pseudotensors was heavily criticized in 1917 by Erwin Schrodinger and others.

Question: "Who's theory did not have a more precise symmetry for conserved energy and momentum?"

Response: "Noether"
OPTIONS:
- no
- yes

A: yes

Problem: Earth processes have not changed over time. The way things happen now is the same way things happened in the past. Mountains grow and mountains slowly wear away. The same process is at work the same as it was billions of years ago. As the environment changes, living creatures adapt. They change over time. Some organisms may not be able to adapt. They become extinct. Becoming extinct means they die out completely. Some geologists study the history of the Earth. They want to learn about Earths past. They use clues from rocks and fossils. They use these clues to make sense of events. The goal is to place things in the order they happened. They also want to know how long it took for those events to happen.

Question: "If Earths processes do not change, what does?"

Answer: "Process"

OPTIONS:
- no
- yes
Answer: no

Question:
Right after the Pentagon was hit, NEADS learned of another possible hijacked aircraft. It was an aircraft that in fact had not been hijacked at all. After the second World Trade Center crash, Boston Center managers recognized that both aircraft were transcontinental 767 jetliners that had departed Logan Airport. Remembering the "we have some planes" remark, Boston Center guessed that Delta 1989 might also be hijacked. Boston Center called NEADS at 9:41 and identified Delta 1989, a 767 jet that had left Logan Airport for Las Vegas, as a possible hijack. NEADS warned the FAA's Cleveland Center to watch Delta 1989. The Command Center and FAA headquarters watched it too. During the course of the morning, there were multiple erroneous reports of hijacked aircraft. The report of American 11 heading south was the first; Delta 1989 was the second. NEADS never lost track of Delta 1989, and even ordered fighter aircraft from Ohio and Michigan to intercept it. The flight never turned off its transponder. NEADS soon learned that the aircraft was not hijacked, and tracked Delta 1989 as it reversed course over Toledo, headed east, and landed in Cleveland. But another aircraft was heading toward Washington, an aircraft about which NORAD had heard nothing: United 93. United Airlines Flight 93 FAA Awareness. At 9:27, after having been in the air for 45 minutes, United 93 acknowledged a transmission from the Cleveland Center controller. This was the last normal contact the FAA had with the flight. Less than a minute later, the Cleveland controller and the pilots of aircraft in the vicinity heard "a radio transmission of unintelligible sounds of possible screaming or a struggle from an unknown origin." The controller responded, seconds later: "Somebody call Cleveland?"This was followed by a second radio transmission, with sounds of screaming. After reading the above, is "Delta 1989" the correct answer to the question "Which flight did NEADS think was hijacked right after the Pentagon was hit?"? OPTIONS:
- no
- yes

Answer:
yes

The center of an atom is held together by powerful forces. This gives them a huge amount of stored energy. This type of energy is called nuclear energy. This energy can be released and used to do work. This happens in nuclear power plants where they split apart the nucleus of an atom. This splitting apart is called nuclear fission. Another type of nuclear energy happens in the Sun. Here the atoms nuclei are not split apart. Instead, the nuclei of the atoms are fused, or joined together. This process is called nuclear fusion. Some of the suns energy travels to Earth. This energy from nuclear fusion warms the planet and provides the energy for photosynthesis.

Question: "What can be done with the stored energy that holds the center of atoms together?"

OPTIONS:
- no
- yes

Answer: "Photosynthesis"

Response:
no