b. Gravitational constant
Explanation:
G in the universal gravitation formula represents the gravitation constant. It's value is  2.071×10⁻⁴³ s²⋅m⁻¹⋅kg⁻¹.
- The law of universal gravitation states that "the gravitational force between two bodies is directly proportional to the product of their masses and inversely proportional to the square of the distance separating them". 
Mathematically, the law is expressed as: 
             F = G
Where F is the gravitational force
             G is the gravitational constant
             r is the distance 
             m is the mass 1 and 2 bodies
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Radioimmunoassay (RIA) is a test that combines radioactive chemicals and antibodies to detect minute quantities of substances in a patient's blood.
In 1959, biophysicist Rosalyn Yalow and physician Solomon A. Berson developed a sensitive method for measuring very small amounts of a substance in the blood called radioimmunoassay (RIA).
Radioimmunoassay (RIA) is a technique that make use of radioisotopes, usually iodine-125, as a tag or label for the detection of antigen. This technique determines the concentration of an antigen based on the competitive binding between radiolabeled and unlabeled antigen for its specific high affinity antibody.
 It is very sensitive that it can measure concentrations up to 0.001 μg/ml.
To know more about radioimmunoassay: brainly.com/question/25654772
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Answer:
true 
Explanation:
because thier are two slopes 
 
        
                    
             
        
        
        
Answer: first 2 statements ie. It is essential that our diet provides these amino acids.
There are 20 essential amino acids.
 
        
             
        
        
        
Mutations are simply a change in genes. So mutations usually result in variation of an organism that can be good or bad. Some mutations can result in physical and mental disorders like Stockholm disease or down syndrome, Where else some mutations can cause immune to diseases that are harmful.