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Tuesday, June 9, 2015
What is global warming?
Extra
carbon dioxide in the atmosphere enhances a natural process known as the
greenhouse effect. Greenhouse gases, such as carbon dioxide, absorb heat and
release it slowly. Without this process, Earth would be too cold for life to
survive. Over the past 200 years mankind has increased the proportion of
sphere, primarily by burning fossil fuels. The higher levels of greenhouse
gases causing our planet to warm-global warming. Also gradual increase in the overall
temperature of the earth's atmosphere generally attributed to the greenhouse
effect caused by increased levels of carbon dioxide, chlorofluorocarbons, and
other pollutants.
Sunday, June 7, 2015
The heart circulatory system
Heart circulatory system
We are going to speak about the heart how it work in our body but before we start we have single circulation system and double circulation system. The deferens between single circulation and double circulation .Single circulation system : the blood is pumped from the heart to the gas exchange and directly to the rest of the body .But the double circulation system: the blood is pumped from the heart to the gas exchange organ back to the heart and then to the rest of the body. Know we are going to speak about double circulation system how it works in human body.
The
heart consists of four parts Right, left atrium it is in the top of the heart
and right, left ventricle this is down of the heart as we can see from the
photo. Also we have two circulations pulmonary and systemic. There are also two
valves that allow the blood to move in the heart. The pulmonary is the small
circulation it works like this: it take the blood from the right ventricle with carbon dioxide and filtrate it in the lungs to oxygen after this it goes to the left atrium.
The systemic is the biggest circulation it work like this: it take the filtrate
blood from left ventricle with oxygen and
pass it to the all of the body, in the capillaries oxygen change to carbon dioxide after this
go to right atrium with carbon dioxide and start to repeat the circulation again and again.
This the first way that the heart can work. Secondly is medulla it is in the
brain that can make the heat work if there is a problem in the heart.
Is global warming really caused by humans?
Global warming caused by humans?
Since 1958 scientists observing in Hawaii have taken continuous measurements of atmospheric carbon dioxide. The levels go up and down by changing the seasons, but overall they show a relentless rise. Bubbles of gas from ice cores and the chemical composition of fossil shells provide us with a record of atmospheric carbon dioxide going back millions of years. There have been warm periods in the past where carbon dioxide was at levels similar to those seen today. However, the rate of change that we see today is exceptional: carbon dioxide levels have never risen so fast. By 2000 they were 17% higher than in 1959. Accompanying this rapid increase in carbon dioxide we see a rise in average global temperatures. Warming in the past 100 years has caused about a 0.8 C increase in global average temperature. Eleven of the 12 years in the period 1995 - 2006 rank among the top 12 warmest years since 1850. There is little doubt that humanity is responsible for the rapid rise in carbon dioxide levels. The rise in temperature that has accompanied our fossil fuel addiction seems too much of a coincidence to just chance. Most people now agree that our actions are having an effect on Earth's climate.
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