Answer:
c) kg
Explanation:
Kilograms stands alone. It has to be hooked up to another unit for it to be a derived unit.
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Answer:
B) 2
Explanation:
Significant figures : The figures in a number which express the value -the magnitude of a quantity to a specific degree of accuracy is known as significant digits.
The rule apply for the multiplication and division is :
The least number of significant figures in any number of the problem determines the number of significant figures in the answer.
The rule apply for the addition and subtraction is :
The least precise number present after the decimal point determines the number of significant figures in the answer. 
(3.478-2.31) = 1.168 ≅ 1.17 (Rounded to least decimal digit)
(4.428-3.56) = 0.868 ≅ 0.87 (Rounded to least decimal digit)
So, 
1.17 * 0.87 = 1.0  (Rounded to least significant)
Answer - two significant digits
 
        
             
        
        
        
Dichlorine monoxide has the same structure like that of water. So, this is a polar molecule. For polar molecules, the dominant intermolecular force would be dipole-dipole forces. For HBr, there is a force between two oppositely charged ions, H⁺ and Br⁻. So, the dominant intermolecular force is electrostatic attraction.