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Vaselesa [24]
3 years ago
7

6th grade science please answer both ! :))

Chemistry
1 answer:
Elanso [62]3 years ago
4 0

Answer:

21. Erosion causes physical changes. For example - Land degradation, deforestation.

20. B statement is closely related to climate.

hope it helps!

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Which element would mostly have chemical properties similar to that of magnesium (Mg)?
DanielleElmas [232]

The elements of same group are placed in same group as they have similar properties. So Calcium is the element which resembles Mangesium.

Calcium and Magnesium both are alkaline earth metals.

They have similar properties as they have similar outer or valence shell electronic configuration

The general electronic configuration of alkaline earht metal is ns2

The electronic configuration of Mg [atomic number 12] and Ca [atomic number 20] are

[Ne]3s^{2}  and [Ar]4s^{2} respectively.


7 0
3 years ago
Estimate the air pressure at an altitude of 5km
r-ruslan [8.4K]
The answer is 100 kg
6 0
3 years ago
The half life for the decay of carbon-14 is 5.73 x 10 years. Suppose the activity due to the radioactive decay of the carbon-14
Elena-2011 [213]

Answer:

Age of the atifact is 4.2\times 10^{2} years

Explanation:

  • For first -order radioactive decay- A_{t}=A_{0}(\frac{1}{2})^{\frac{t}{t_{\frac{1}{2}}}}
  • A_{t} represents activity of radioactive nuclide after t time, A_{0} represents initial activity of radioactive nuclide and t_{\frac{1}{2}} represents half-life
  • Here, A_{t}=19Bq, A_{0}=20Bq and t_{\frac{1}{2}}=5.73\times 10^{3}years

Plug-in all the given values in the above equation-

19=20\times (\frac{1}{2})^{\frac{t}{5.73\times 10^{3}}}

or, t=4.2\times 10^{2}

So, age of the atifact is 4.2\times 10^{2} years

6 0
3 years ago
PLS HELP!!!!!! I will give brainly-ist
azamat

Answer:

A biology investigation usually starts with an observation—that is, something that catches the biologist’s attention. For instance, a cancer biologist might notice that a certain kind of cancer can't be treated with chemotherapy and wonder why this is the case. A marine ecologist, seeing that the coral reefs of her field sites are bleaching—turning white—might set out to understand why.

How do biologists follow up on these observations? How can you follow up on your own observations of the natural world? In this article, we’ll walk through the scientific method, a logical problem-solving approach used by biologists and many other scientists.

Explanation:

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3 years ago
At 40 Centigrade kW is?
Schach [20]

Answer:

yee

Explanation:yee

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