Answer: Even though the genetic susceptibility plays a crucial role on the IQ of the individual, various modifiable environmental factors like education, premature birth, nutrition, pollution, drug and alcohol abuse, mental illnesses, and diseases can have an influence on an individual's IQ.
Hardness
streak color
luster
cleavage/fracture
reference rable
The right answer is
2) NaCl
In fact, from the definition of acid, all acids contain at least one atom of hydrogen. In the options given by the problem, all compounds contain at least one atom of hydrogen H, except for the NaCl: therefore, NaCl is not an acid.