Read the following article and select the best answer. Article: Dogs can be worried and pessimistic just like people, researchers report in a new study in Current Biology. And they aren't talking about basset hounds : those dogs just look as if they expect the worst. What the scientists say is that dogs that exhibit anxiety when left home alone by their owners may have bigger problems -- they may be in a permanent bad mood. This pessimistic outlook may not otherwise be easily apparent in a dog's other characteristics, like running speed or learning ability, the study reports. Dogs are similar to humans in the role that emotional state plays in decision making, said Michael Mendel, a veterinary scientist at the University of Bristol and the study's lead author. The study's researchers looked at 24 dogs in shelters in Britain. They placed the dogs in isolated settings and observed their reactions -- many barked, jumped on furniture and scratched at the door. Then they placed bowls in two rooms. One bowl contained food, while another was empty. After training the dogs to understand that bowls can sometimes be empty, and sometimes full, they began to place bowls in ambiguous locations. Dogs that quickly raced to the locations were more optimistic, and in search of food. Those that did not were deemed pessimistic. The more separation anxiety a dog expressed while in isolation, the more likely the dog was to have a pessimistic reaction, the researchers found. The study carries an important message for dog owners, Dr. Mendel said. Dogs that express serious anxiety when alone may need treatment, as it could be a sign of unhappiness and instability. Question: According to Dr. Mendel, which statement is true? - Like humans, dogs are good at decision making. - Dog owners should train dogs to find food. - Emotional state works sometimes when humans make decision. - Dogs can always find the bowl with food quickly.
Emotional state works sometimes when humans make decision.

Read the following article and select the best answer. Article: The year is 2094. It has been announced that a comet is heading towards the Earth . Most of it will miss our planet, but two pieces will probably hit the southern half of the Earth. On 17 July , a piece four kilometers wide enters the Earth's atmosphere with a massive explosion . About half of the piece is destroyed, but the remaining part hits the South Atlantic at 200 times the speed of sound. The sea boils and a huge hole is made in the sea bed. Huge waves are created and spread outwards from the hole. The wall of water, a kilometer high, rushes towards southern Africa at 800 kilometers an hour. Cities on the African coast are totally destroyed and millions of people are drowned. Before the waves reach South America, the second piece of the comet lands in Argentina. Earthquakes and volcanoes are set off in the Andes Mountains. The shock waves move north into California and all around the Pacific Ocean. The cities of Los Angeles, San Francisco and Tokyo are completely destroyed by earthquakes. Millions of people in the southern half of the earth are already dead, but the north won't escape for long. Because of the explosions, the sun is hidden by clouds of dust, temperatures around the world fall to almost zero .Crops are ruined. The sun won't be seen again for many years. Wars break out as countries fight for food. A year later, no more than 10 million people remain alive. Could it really happen? In fact, it has already happened more than once in the history of the Earth. The dinosaurs were on the Earth for over 160 million years. Then 65 million years ago they suddenly disappeared. Many scientists believe that the Earth was hit by a piece of object in space. The dinosaurs couldn't live through the cold climate that followed and they died out. Will we meet the same and? Question: Why can't the northern half of the earth escape for long? - Because the land is covered with water - Because the light and heat from the sun can not reach the earth. - Because people there can not live at the temperature of zero. - Because wars break out among countries.
Because the light and heat from the sun can not reach the earth.

Q: Read the following article and select the best answer. Article: Ears are for hearing -- everyone knows that. But for a creature called the Cuvier's beaked whale, hearing starts in the throat, a new study found. The observation might help explain how all whales hear. The work might also help scientists understand how animals are affected by underwater sonar . This sonar, used by some ships, sends out sound waves to locate underwater objects. The Cuvier's beaked whale is a so-called toothed whale. Toothed whales dive deep into the ocean in search of food. As the whales hunt, they produce sounds that reach objects and then return to the whales. This allows the animals to "see" the shape, size, and location of objects, even when they're 1,000 meters under the sea, where it is totally dark. To better understand how the whale hears, researchers from San Diego State University in California took X-rays of two Cuvier's beaked whales. The whales had died and washed up on the beach. Ted Cranford and his colleagues used the images to make a computer model of a Cuvier's beaked whale's head. Then, they modeled the process of sound traveling through the head. The researchers knew that some sounds get to the ears of a toothed whale through a structure called "the window for sound". Found on the lower jaw, this structure is very thin on the outside and has a large pad of fat on the inside. When the researchers used their computer model to work out how sound waves travel in the whale's head, they were surprised to find that sounds coming from right in front of the whale actually travel under the animal's jaw. From there, sound waves move through the throat, into a hole in the back of the jaw, and finally to the pad of fat near the animal's ears. Cranford guesses that other types of whales may hear through their throats. Further testing is needed to be sure. Eventually, the insight into how whales hear might explain whether sonar testing by military ships is causing the animals to wind up on beaches. Question: Toothed whales look for food under the sea by _ . - watching the shape and size of their objects - diving deep into the sea - sending and receiving sounds - making lots of noises
A: sending and receiving sounds

*Question*
Read the following article and select the best answer. Article: Summer Science Class registration begins on March 8 ! If you are interested in science,the environment,or conservation and you are in grades 7-12,sign up soon for Black Rock Forest Consortium's Summer Science Class program. You can download the Summer Science Classes 2013 brochure here. It is easy to register;just call 8455344517 or click here. Twelve weeklong courses in the natural sciences and the arts are offered at Black Rock Forest in Cornwall from July 15 through August 9.Two more classes are offered with site partners,including "The Art of Scientific Observation," hosted jointly by Black Rock Forest Consortium and Storm King Art Center,one of the world's leading sculpture parks,and "A Nautical Expedition" hosted jointly by the Consortium and the Constitution Marsh Audubon Center. We are delighted to announce two special "away" classes that are part of the Summer Science Class program this year: an "Adirondack EcoAdventure" beginning August 11,and "Conservation Biology in Florida," beginning June 23 and featuring field work on the Gulf Coast in cooperation with the University of Florida's Seahorse Key Marine Biological Laboratory. For more information on the Summer Science Class program,please read our press release. Black Rock Forest Consortium is a nonprofit organization founded in 1989 to advance scientific understanding of the natural world through research,education and conservation programs. Question: Where can you find the article? - From a web site. - From a traveling brochure. - From a novel book. - From one famous magazine.
**Answer**
From a web site.