Answer:
Valency is defined as the number of hydrogen atoms which combine directly or indirectly with one atom of an element.
Example:
One atom of nitrogen combines with three atoms of hydrogen to form ammonia gas. So, the valency of nitrogen is 3.
According to Arrhenius definition of acids, 
is an acid.
According to Arrhenius definition of acids and bases, acid is any substance that produces hydrogen ion in solution as its only positive ion.
Following this definition, let us now consider what happens when is introduced into a water;
(aq)-------> NH3(aq) + 
(aq)
Hence, according to Arrhenius definition of acids, is an acid.
For another example of Arrhenius acids, see
brainly.com/question/516295
Answer:
Because Scientists Uses hypothesis and try tests and try proving their points while regular normal people use it to just state a statement
Answer:
There are One million micrograms in a gram
Explanation:
A microgram is one Millionth of a gram therefore it take one million of them to equal one gram
