问答题保函

问答题Earth is unique in the Solar System as being the only planet which is able to support life in all its forms: from basic living micro-organisms to highly sophisticated and intelligent human beings. There are many reasons why this happens.【】REASON ONE: ATMOSPHERE Earth has a breathable atmosphere. Oxygen is the gas that is required for the life of most creatures. This is present in Earth' s atmosphere and also in water. Oxygen is constantly put into the atmosphere by plants and trees. Earth' s atmosphere also contains a small amount of carbon dioxide. This is a poisonous gas which makes up most of the atmosphere of planets like Venus and Mars and makes them unable to support human life.【】REASON TWO: CLIMATE Earth has a suitable climate. This is caused by the moderate amount of carbon dioxide in the planet' s atmosphere, which is constantly refreshed whenever there is a volcanic eruption. The temperature on Earth does not go from one extreme to the other either. Mercury can be anything from 200° c below freezing to 375° c above. At 375° c, water would only exist as a gas, and the planet would be completely dry.【】REASON THREE: WATER Earth has water! Water is believed to be the most important chemical necessary for life. It contains the oxygen needed for life. Other liquids contain poisonous elements. Water doesn' t burn skin (like liquids containing acids do) , it is drinkable, and it allows life-providing molecules to move around easily. Other moons in the Solar System, such as Europe, a moon of Jupiter, are believed to have oceans of water under its icy surface.【】REASON FOUR: LIGHT All planets receive light from the Sun, but no planet uses it as usefully as Earth. Trees and plants on the planet produce oxygen through a process called photosynthesis. Plants need the Sun to grow. Look at plants in windows and notice how they usually seem to grow towards the Sun. Try growing a plant in a dark room and in a light room. Notice which one grows quicker. The one which has grown quickest is the one which also produces more oxygen. It is believed that if we were able to get plants to grow on another planet, such as Mars, they would begin putting oxygen into the planet' s atmosphere and increase the possibility of life. Saturn' s moon, Titan, has an atmosphere containing mainly nitrogen. If this moon was to possess oxygen too in its atmosphere, by a plant photosynthesising on it, it could have a similar atmosphere to Earth. Something else which helps the plants to photosynthesise on Earth is the length of time the planet takes to spin once on its axis. Taking just under 24 hours means that each side of the planet receives sunlight regularly. If we look at a planet like Venus, which takes 243 days to spin on its axis, it means that for a large period of time certain parts of the planet are in complete darkness. So even if the planet could support life, it would struggle to do so.【】REASON FIVE: THE SUN All of the reasons given above for life existing on Earth are only possible because of one main reason. The Sun! Put simply, if there was no Sun, there would be no life on Earth. Where would Earth go? The Sun' s gravity keeps Earth in its orbit, but if the Sun vanished, Earth would simply float away.

问答题Store Away from Boiler

问答题Russian ruble

问答题我们屋后有半亩隙地。母亲说：“让它荒芜着怪可惜，既然你们那么爱吃落花生，就辟来做花生园罢。”我们几姐弟和几个小丫头都很喜欢——买种的买种，动土的动土，灌园的灌园；过不了几个月，居然有收获了!

问答题B/L

问答题UNSC

问答题emotional office abuse

问答题服务型政府

问答题利改税

问答题IOU

问答题FIFA

问答题经贸关系历来是中美关系的重要组成部分，也是两国交往中最为活跃的一个方面。自1979年中美建交以来，双边经贸关系虽受两国总体关系的影响，经历了一些波折，但长期以来一直保持较快发展速度。中美两国经济上的相互依存在不断加强，经贸关系已成为中美关系的稳定器。随着中国深入改革和扩大开放进程的发展，特别是中国加入世贸组织后，经贸关系在中美关系发展中将发挥更大的作用。

问答题inverse translation

问答题中国制造2025

问答题consumer price index(CPI)

问答题支付宝

问答题Humanitarian crisis

问答题If people mean anything at all by the expression "untimely death", they must believe that some deaths run on a better schedule than others. Death in old age is rarely called untimely—a long life is thought to be a full one. But with the passing of a young person, one assumes that the best years lay ahead and the measures of that life were still to be taken. History denies this, of course. Among prominent summer deaths, one recalls those of Marilyn Monroe and James Deans, whose lives seemed equally brief and complete. Writers cannot bear the fact that poet John Keats died at 26, and only half playfully judge their own lives as failures when they pass that year. The idea that the life cut short is unfulfilled is illogical because lives are measured by the impressions they leave on the world and by their intensity and virtue.

问答题the “Mathew Effect”