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?"

Answer: "Noether"

Response: yes

Little is known of the earliest Stone Age inhabitants of Europe's southwestern extremity. The ancient Greeks called them the Cynetes (or Cunetes). Whatever their origins, their culture evolved under the pressure and influence of foreign forces. Among the many invading armies that settled here and contributed to nascent Portuguese culture were Phoenicians, who settled in the area around 1,000 b.c., followed by the Celts, Iberians, Greeks, and Carthaginians. But it was the Romans, who arrived late in the third century b.c., who most greatly influenced all of Iberia. They built towns, industries, roads, and bridges, developed agriculture, and bequeathed the Latin language, of which Portuguese is a direct descendant. The Romans named the southwestern province of the peninsula Lusitania, oddly enough for one of the Celtiberian tribes they defeated, and by the third century a.d. had introduced Christianity. By the beginning of the fourth century the Algarve had a bishop in place, based in Faro. But Rome had already fallen into decay, and soon hordes of northern tribesmen took over the empire. The Algarve fell to the Visigoths in the mid-fifth century. Under Moorish Rule In a.d. 711, the Moors brought powerful armies from North Africa and launched a devastating attack on the Iberian peninsula, conquering much of what would become Spain and Portugal. They imposed Islam and left an indelible influence on the countryside and the population of the Algarve. The Moorish legacy can still be seen in the form of wells and waterwheels, squat white houses, the dark complexions of the people, and in the very name given the regiontaken from Al-Gharb, which means "country of the west" (when the Moors conquered the territory, it was the most westerly in the known world). The Moors governed their Iberian kingdoms from across the border in Seville, but the Algarve had its own regional capital and huge, invulnerable fortress. The capital was Chelb (or Xelb), and it was bigger and better defended than Lisbon. Today the town, known as Silves, is a provincial outpost whose only besiegers are busloads of tourists who climb the narrow streets up to the old Moorish ramparts.

Question: "What were the Romans able to accomplish when they invaded Iberia? Name two things."

Answer: "Made houses, farmed"

Response: no

The Creed family moves into a new home , close to a road where truckers often drive unsafely . They befriend their neighbor , Jud Crandall , who tells them about a nearby pet cemetery which was built on Indian burial grounds and is rumored to be haunted . Later , Louis Creed , working at the University of Maine at Orono health center , treats Victor Pascow , who has been hit by a truck and incurred massive head injuries . Pascow dies after grabbing Louis , addressing him by name , and uttering a cryptic message . He also promises to '' come to '' him . That night , in what is seemingly a dream , Victor visits Louis , warning him about the burial ground beyond the pet cemetery . Louis wakes up to find his feet covered in dirt . Church , a cat owned by Louis ' daughter Ellie , is killed by a truck on the road in front of their house while Rachel , Ellie and Gage are in Chicago . Jud takes Louis to an ancient Micmac Indian burial ground beyond the pet cemetery they visited earlier and buries the cat . Church is brought back to life , but is an evil shell of himself . He attacks Louis and reeks of decomposition . Louis asks if a person was ever buried in the grounds . Jud replies , '' Christ on His throne , no. . And whoever would? '' Sometime later , Louis ' young son Gage is killed by a truck on the same road . Louis considers burying Gage in the burial grounds . Jud tries to dissuade him from doing so , telling him about a young man from town , Timmy Baterman , who died in service during World War II .

Question: "What people are killed by trucks?"

Answer: "Victor Pascow and Jud Crandal"

Response: no

Relying on an animal to come by is risky. A flower may have to wait a long time for the right animals to come by. What if one never passes close enough to the flower? Hoping the wind will blow is also risky for a plant. What if the wind does not blow? What if the blowing pollen does not land on another flower? The wind could even blow the pollen over the ocean where it is wasted. Giving free nectar is costly. It is not a good use of the plants energy. A plant uses a lot of energy to produce nectar. Some animals may just drink the nectar. They may not carry off any pollen in return. To improve their chances, plants evolved special traits. For example, they developed ways to hide their nectar. Only certain animals were able to get at the plants hidden nectar. These specific animals might be more likely to visit only flowers of the same species. This was also a benefit for some animals. Animals also evolved special traits to get to the nectar.

Question: "How do animals pose a threat to pollination?"

Answer: "Drink nectar without transferring pollen"

Response:
yes