A flood occurs when a river overflows its banks. This might happen because of heavy rains. Floodplains In very flat regions, flood water may spread out on the surface of the land. It then slows down and drops its sediment. If a river floods often, a floodplain develops. A floodplain is an area where a thick layer of rich soil is left behind as the floodwater recedes. Thats why floodplains are usually good places for growing plants. They are very flat areas and they have very rich soils. The Nile River valley is a great example of a floodplain. Each year, the Nile River rises over its banks. This floodwater carries a lot of sediment. This sediment has been eroded off areas of land from upstream. This sediment is dropped as the water slows down after spreading across the land. What is left behind is a very rich soil. Thats why crops can be raised in the middle of a sandy desert. Natural Levees A flooding river often forms natural levees along its banks. A levee is a raised strip of sediments deposited close to the waters edge.

Question: "What makes the floodplains good for growing plants?"

OPTIONS:
- no
- yes

Answer: "Sandy desert"

Response: no

Sometimes traits can vary from parent to offspring. These changes are due to mutations. Mutations are a random change. Mutations are natural. Some mutations are harmful. In this case, the organism may not live to reproduce. The trait will not be passed onto offspring. Others variations in traits have no effect on survival. Can some mutations be good for a living thing? Other mutations can have great benefits. Imagine being the first moth that can blend into its background. It would have a better chance of survival. A living thing that survives is likely to have offspring. If it does, it may pass the new trait on to its offspring. Thats good news for the offspring. The offspring may be more likely to survive. Mutations are one way living things adapt to new conditions.

Question: "What can mutations enable?"

OPTIONS:
- no
- yes

Answer: "Blending in"

Response: yes

We do not know exactly how the hijackers gained access to the cockpit; FAA rules required that the doors remain closed and locked during flight. Ong speculated that they had "jammed their way" in. Perhaps the terrorists stabbed the flight attendants to get a cockpit key, to force one of them to open the cockpit door, or to lure the captain or first officer out of the cockpit. Or the flight attendants may just have been in their way. At the same time or shortly thereafter, Atta-the only terrorist on board trained to fly a jet-would have moved to the cockpit from his business-class seat, possibly accompanied by Omari. As this was happening, passenger Daniel Lewin, who was seated in the row just behind Atta and Omari, was stabbed by one of the hijackers-probably Satam al Suqami, who was seated directly behind Lewin. Lewin had served four years as an officer in the Israeli military. He may have made an attempt to stop the hijackers in front of him, not realizing that another was sitting behind him. The hijackers quickly gained control and sprayed Mace, pepper spray, or some other irritant in the first-class cabin, in order to force the passengers and flight attendants toward the rear of the plane. They claimed they had a bomb. About five minutes after the hijacking began, Betty Ong contacted the American Airlines Southeastern Reservations Office in Cary, North Carolina, via an AT&T airphone to report an emergency aboard the flight. This was the first of several occasions on 9/11 when flight attendants took action outside the scope of their training, which emphasized that in a hijacking, they were to communicate with the cockpit crew. The emergency call lasted approximately 25 minutes, as Ong calmly and professionally relayed information about events taking place aboard the airplane to authorities on the ground. At 8:19, Ong reported:"The cockpit is not answering, somebody's stabbed in business class-and I think there's Mace-that we can't breathe-I don't know, I think we're getting hijacked." She then told of the stabbings of the two flight attendants. At 8:21, one of the American employees receiving Ong's call in North Carolina, Nydia Gonzalez, alerted the American Airlines operations center in Fort Worth, Texas, reaching Craig Marquis, the manager on duty. Marquis soon realized this was an emergency and instructed the airline's dispatcher responsible for the flight to contact the cockpit. At 8:23, the dispatcher tried unsuccessfully to contact the aircraft.

Question: "Which passenger made an attempt to stop the hijackers?"

OPTIONS:
- no
- yes

Answer: "Daniel Lewin"

Response: yes

Moscow (CNN) -- Divers have completed their search of a Russian cruise ship that sank last weekend with the loss of many lives, the Emergency Situations Ministry told CNN Friday. The official death toll has reached 114 -- including 66 women, 28 children and 20 men, the ministry said. The bodies of 15 people are still missing. There were 208 people on the "Bulgaria" at the time of the accident Sunday, of whom 79 were rescued. Divers have checked all the boat's compartments, the ministry said, and are now looking for more bodies around the boat as well downstream on the Volga River, where they could have been carried by the current. The area where search efforts continue has been enlarged to 200 kilometers (125 miles) from the scene, Russian Transport Minister Igor Levitin said at a briefing Friday. Preparations are under way for the cruise ship to be raised from the river bottom in the coming days. Two large boat cranes, one from Moscow and another one from Volgograd, which will be used for the lifting, are on the way to the accident site. "We have asked the Emergency Situations Ministry to keep 23 divers at the scene to continue the search for bodies even during the lifting operation," Levitin said. Specialist military divers were brought in mid-week to aid in the search efforts. Four people face criminal charges over the sinking of the ship, which Russian media have called the most devastating river accident in the country's history.

Question: "What were the divers searching for?"

OPTIONS:
- no
- yes

Answer: "Sunken treasure"

Response:
no