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Chapter 2: 8th, 7th,&6th millennia b.c.

Backward to Beginning to 8000 B.C.

8,000 to 5,000 b.c.-from hunting to agriculture

Although technically this period to be discussed is still prehistorical from the standpoint of its preceding man's ability to write and therefore narrate his exploits, archaeological excavations and other studies have pin-pointed so many activities that it seems worth while to give a separate chapter to these three millennia. In this period there were weather oscillations with rapid changes in climate and corresponding changes in flora and fauna but over all there was improvement toward a more temperate situation. Domestication of some animals occurred and there was early plant cultivation. Domestication involves selective breeding and genetic change so that some species become completely dependent on man's intervention for survival. The yield from cultivated cereals made possible human communities of a larger size than ever before, and thus for the first time there arose settlements which can be described as villages or even towns. The earth's population at 8,000 B.C. has been estimated at 5.3 million (Ref. 222 ). The changed distribution of rainfall and the changes in sea and lake levels after that date necessitated a greater use of the grasses which abounded in the mountain foothills and the selection of certain forms which could be grown in lowland habitats as potential crops. As mankind began to leave food-gathering for an agricultural way of life, 99% of the time during which mankind has existed had already passed. (Ref. 8 , 215 , 221 )

Forward to 5000 to 3000 B.C.

    Choose different region

  • Africa
  • America
  • Central and Northern Asia
  • Europe
  • The Far East
  • The Indian Subcontinent
  • The Near East
  • Pacific

Questions & Answers

so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, A comprehensive outline of world history. OpenStax CNX. Nov 30, 2009 Download for free at http://cnx.org/content/col10595/1.3
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