QUES: Water flowing over Earths surface or underground causes erosion and deposition. Water flowing over a steeper slope moves faster and causes more erosion. How water transports particles depends on their size. When water slows down, it starts depositing sediment. This process starts with the largest particles first. Runoff erodes the land after a heavy rain. It picks up sediment. Runoff carries most of the sediment to bodies of water. Mountain streams erode narrow, V-shaped valleys and waterfalls. Erosion and deposition by slow-flowing rivers create broad floodplains and meanders. Deposition by streams and rivers may form alluvial fans and deltas. Floodwaters may deposit natural levees. Erosion and deposition by groundwater can form caves and sinkholes. Stalactites and stalagmites are mineral deposits. They build up in caves as water continues to drip.
Do you have any questions?
MY QUESTION: What kind of deposits build up in caves as water continues to drip?

QUES: To make certain the U.S. was aware of the danger, in July 1939, a few months before the beginning of World War II in Europe, Szilard and Wigner visited Einstein to explain the possibility of atomic bombs, which Einstein, a pacifist, said he had never considered. He was asked to lend his support by writing a letter, with Szilard, to President Roosevelt, recommending the U.S. pay attention and engage in its own nuclear weapons research. A secret German facility, apparently the largest of the Third Reich, covering 75 acres in an underground complex, was being re-excavated in Austria in December 2014 and may have been planned for use in nuclear research and development. The letter is believed to be "arguably the key stimulus for the U.S. adoption of serious investigations into nuclear weapons on the eve of the U.S. entry into World War II". In addition to the letter, Einstein used his connections with the Belgian Royal Family and the Belgian queen mother to get access with a personal envoy to the White House's Oval Office. President Roosevelt could not take the risk of allowing Hitler to possess atomic bombs first. As a result of Einstein's letter and his meetings with Roosevelt, the U.S. entered the "race" to develop the bomb, drawing on its "immense material, financial, and scientific resources" to initiate the Manhattan Project. It became the only country to successfully develop an atomic bomb during World War II. For Einstein, "war was a disease ... [and] he called for resistance to war." By signing the letter to Roosevelt he went against his pacifist principles. In 1954, a year before his death, Einstein said to his old friend, Linus Pauling, "I made one great mistake in my life--when I signed the letter to President Roosevelt recommending that atom bombs be made; but there was some justification--the danger that the Germans would make them ..."
Do you have any questions?
MY QUESTION: What was arguably the key stimulus for the U.S. adoption of serious investigations into nuclear weapons on the eve of the U.S. entry into World War II?

QUES: Living things need non-living matter as well as energy. What do you think matter is used for? One thing is to build bodies. They also need it to carry out the processes of life. Any non-living matter that living things need is called a nutrient. Carbon and nitrogen are examples of nutrients. Unlike energy, matter is recycled in ecosystems. You can see how in Figure 3.11. Decomposers release nutrients when they break down dead organisms. The nutrients are taken up by plants through their roots. The nutrients pass to primary consumers when they eat the plants. The nutrients pass to higher level consumers when they eat lower level consumers. When living things die, the cycle repeats.
Do you have any questions?
MY QUESTION: What do living things need?

QUES: 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.
Do you have any questions?
MY QUESTION:
Where does the sediment in a flooding river come from, and where does it eventually come to rest?