You are given a new situation: Two rivers spring from the same mountain. Olt was a fast moving river, while Mures river was slow moving and deep. Both rivers are very important for the local economies. and a hint : The major zones in river ecosystems are determined by the river bed's gradient or by the velocity of the current. Faster moving turbulent water typically contains greater concentrations of dissolved oxygen, which supports greater biodiversity than the slow moving water of pools. These distinctions form the basis for the division of rivers into upland and lowland rivers. The food base of streams within riparian forests is mostly derived from the trees, but wider streams and those that lack a canopy derive the majority of their food base from algae. Anadromous fish are also an important source of nutrients. Environmental threats to rivers include loss of water, dams, chemical pollution and introduced species. A dam produces negative effects that continue down the watershed. The most important negative effects are the reduction of spring flooding, which damages wetlands, and the retention of sediment, which leads to loss of deltaic wetlands. Please answer this question : Which river had a food source mostly derived from the trees?
----
Answer: Olt

You are given a new situation: Ken and Stacy are two engineers discussing their plans about what source of energy they should use to generate electricity in a new city they are helping design. Ken feels that they should use coal since it's reliable, abundant and relatively cheap. Stacy argues that they should use solar power because there is an infinite supply of solar energy. and a hint : Another major cause of extinction is global warming , which is also known as global climate change. During the past century, the Earth's average temperature has risen by almost 1C (about 1.3F). You may not think that is significant, but to organisms that live in the wild and are constantly adapting to their environments, any climate change can be hazardous. Recall that burning fossil fuels releases gasses into the atmosphere that warm the Earth. Our increased use of fossil fuels, such as coal and oil, is changing the Earth's climate. Any long-term change in the climate can destroy the habitat of a species. Even a brief change in climate may be too stressful for an organism to survive. For example, if the seas increase in temperature, even briefly, it may be too warm for certain types of fish to reproduce. Please answer this question : Which person's plan will kill more animals?
----
Answer: Ken

You are given a new situation: John wanted to make some lighted signs for his business. To that end, he chose noble gases, neon, krypton, and xenon. First, he kept the noble gases in containers. He called it step A. Then he passed electric current through them. He called it step B. In the process, he came up with three signs, sign A, sign B, and sign C. Sign A used neon. Sign B used krypton, and sign C used xenon. and a hint : Noble gases are also used to fill the glass tubes of lighted signs like the one in the Figure below . Although noble gases are chemically nonreactive, their electrons can be energized by sending an electric current through them. When this happens, the electrons jump to a higher energy level. When the electrons return to their original energy level, they give off energy as light. Different noble gases give off light of different colors. Neon gives off reddish-orange light, like the word "Open" in the sign below. Krypton gives off violet light and xenon gives off blue light. Please answer this question : In step B would the electrons be in the higher or lower energy level than in step A?
----
Answer:
higher