How do erosion and deposition work together to form sand dunes?

How long does novocaine take to wear off?

Inessa05 [86]

Novocaine is a logal anesthetic agent which is commonly used during dental procedures or other oral processes. This causes numbness of the infected area so that the patients will not feel the pain. This is a local name for procaine which was discovered by the German chemist named Alfred Einhorn in 1905.

The duration to which we expect the numbness varies to the different factors. The factors include the location of the application, the area, concentration, and presence of other anesthetic chemical. It is expected at least that novocaine will last for 1.5 to 3 hours.

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3 years ago

1. What was the accepted belief in the origin of life in the 19th century?

coldgirl [10]

Answer:

As evolution became widely accepted in the 1870s, caricatures of Charles Darwin with the body of an ape or monkey symbolised evolution.

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3 years ago

Two primary factors of Extinction

zaharov [31]

introduction,disease

5 0

2 years ago

Read 2 more answers

How does the carbon cycle affect climate change and global warming on our planet? (Think about the different ways that carbon is

Lilit [14]

Answer:

Explanation:

The amount of global warming will depend on the magnitude of future emissions, which, in turn, depends on how society grows and develops. The rate of warming will also depend on how sensitive the climate is to increased atmospheric greenhouse gases.

Yet climate change also depends on an under-appreciated factor known as “carbon-cycle feedbacks”. Accounting for uncertainties in carbon-cycle feedbacks means that the world could warm much more – or a bit less – than is commonly thought.

The carbon cycle is the collection of processes that sees carbon exchanged between the atmosphere, land, ocean and the organisms they contain. “Feedbacks” refer to how these processes could change as the Earth warms and atmospheric CO2 concentrations rise.

The commonly used warming projections – those highlighted in Intergovernmental Panel on Climate Change (IPCC) assessment reports – include a single best-estimate of carbon-cycle feedbacks. But they do not account for the large uncertainties in these estimates.

These uncertainties are “one of the dominant sources” of divergence between different model projections, according to Dr Ben Booth and colleagues at the Met Office Hadley Centre.

Climate campaigners, such as Greta Thunberg, have also expressed concern that climate projections typically do not fully incorporate the potential range of carbon-cycle feedbacks.

This article explores the implications of carbon-cycle feedback uncertainties by examining a number of modelling studies conducted by scientists over the past decade. These studies give a similar central estimate of carbon-cycle feedbacks to those used in IPCC projections.

But, at the high end, the results show these feedbacks could push atmospheric concentrations of greenhouse gases much higher – meaning more warming – from the same level of emissions.

Analysis for this article shows that feedbacks could result in up to 25% more warming than in the main IPCC projections.

Importance of carbon-cycle feedback uncertainties

Today, around half of the CO2 emitted by humans remains in the atmosphere, with the remainder absorbed by the oceans and land. However, as the Earth warms this is expected to change. For example, warming reduces the amount of CO2 absorbed by surface ocean waters and the amount of carbon sequestered in soils. It can also accelerate tree death and the risk of wildfires. Thawing permafrost may release additional carbon into the atmosphere. Overall, the carbon cycle is expected to weaken as a result of climate change, leading to more emissions remaining in the atmosphere and less being absorbed by the land and oceans. All of these processes introduce uncertainty when translating future CO2 emissions into changes in atmospheric CO2 concentrations.

Changes in carbon cycle behavior as the Earth warms is an example of a climate feedback – a self-reinforcing change to the Earth’s temperature from a secondary factor. Not all of these feedbacks will necessarily act to increase temperature, however. CO2 fertilisation effects can lead to additional vegetation growth, sequestering more carbon. Nitrogen cycle changes can also enhance land uptake of carbon. Dynamic vegetation changes in response to a warming climate – which account for potential vegetation shifts as regional climate change – also have important, but uncertain effects on the carbon cycle.

6 0

2 years ago

What idea is Malthus known for?

jenyasd209 [6]

<span>ogy of Human Populations: Thomas MalthusThomas Malthus (1766-1834) has a hallowed place in the history of biology, despite the fact that he and his contemporaries thought of him not as a biologist but as a political economist. Malthus grew up during a time of revolutions and new philosophies about human nature. He chose a conservative path, taking holy orders in 1797, and began to write essays attacking the notion that humans and society could be improved without limits.Population growth vs. the food supply
Malthus’ most famous work, which he published in 1798, was An Essay on the Principle of Population as it affects the Future Improvement of Society. In it, Malthus raised doubts about whether a nation could ever reach a point where laws would no longer be required, and in which everyone lived prosperously and harmoniously. There was, he argued, a built-in agony to human existence, in that the growth of a population will always outrun its ability to feed itself. If every couple raised four children, the population could easily double in twenty-five years, and from then on, it would keep doubling. It would rise not arithmetically—by factors of three, four, five, and so on—but geometrically—by factors of four, eight, and sixteen.<span>
Between 1800 and 2000 the human population increased about six-fold. Has the food supply kept pace? Will there be enough food to support the projected population of 9.2 billion in 2050?</span>If a country’s population did explode this way, Malthus warned that there was no hope that the world’s food supply could keep up. Clearing new land for farming or improving the yields of crops might produce a bigger harvest, but it could only increase arithmetically, not geometrically. Unchecked population growth inevitably brought famine and misery. The only reason that humanity wasn’t already in perpetual famine was because its growth was continually checked by forces such as plagues, infanticide, and simply putting off marriage until middle age. Malthus argued that population growth doomed any efforts to improve the lot of the poor. Extra money would allow the poor to have more children, only hastening the nation’s appointment with famine.A new view of humans
Malthus made his groundbreaking economic arguments by treating human beings in a groundbreaking way. Rather than focusing on the individual, he looked at humans as groups of individuals, all of whom were subject to the same basic laws of behavior. He used the same principles that an ecologist would use studying a population of animals or plants. And indeed, Malthus pointed out that the same forces of fertility and starvation that shaped the human race were also at work on animals and plants. If flies went unchecked in their maggot-making, the world would soon be knee-deep in them. Most flies (and most members of any species you choose) must die without having any offspring. And thus when Darwinadapted Malthus’ ideas to his theory of evolution, it was clear to him that humans must evolve like any other animal.
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3 years ago