Imagine you are a detective examining a crime scene. you are trying to
identify the person who committed the crime, so you collect many samples at
the crime scene. which sample would be most useful in identifying the
person who committed the crime?
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a. a newspaper left at the crime scene
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b. an ant found crawling across the crime scene
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c. pieces of hair found at the crime scene
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d. gravel and dirt on the ground at the crime scene
submit

C. Pieces of hair found at the crime scene.

Explanation:

Pieces of hair found at the crime scene is more useful to find the criminal who committed the crime, because it helps in indetifying criminal's DNA through the process of DNA fingerprinting. The hair is analyzed by the chemical makeup of the hair and extracting DNA from the hair follicle, pieces of hair must have hair follicle attached to find DNA of the criminal.  

Nuclear DNA can be successfully extracted from the hair root. Cut hair samples are useless without hair follicle attached. Its DNA will be useful only few months for testing. The DNA last in hairs about 1,000 to 10,000 years.

how to make a simple air condition

a mercury barometer is a device that uses the physical properties of mercury in a tube to measure barometric pressure. mercury barometers are used for : -

1. measurement of atmospheric pressure  

2. determining the altitude of a place

3. weather forecasting

4. calibration and checking of aneroid barometers

5. application in fluid mechanics

6. measurement of pressure in aircrafts

7. surface weather analysis

8. preparation of barographs

9. usage in physical sciences like physics, astronomy & chemistry

10. preparation of aircraft altimeters

characteristics of mercury barometer : -

1.used to define and measure atmospheric pressure.

2.on the average at sea level the column of mercury rises to a height of about 760 mm.

3.this quantity is equal to 1 atmosphere.

4.it is also known as standard atmospheric pressure.

5.a barometer in which the weight of a column of mercury in a glass tube with a sealed top is balanced against that of the atmosphere pressing on an exposed cistern of mercury at the base of the mercury column, the height of the column varying with atmospheric pressure.