Question wants to fill in the blanks for the given statement.
"2 roots is called _______ radicals".
It seems that you are looking for specific name of the root for the given statement.
Name of the radical is identified by the index of the given radical.
If the index is 2 then we call it square root.
If the index is 3 then we call it cube root.
If the index is 4 then we call it 4th root.
Similarly if the index is "n" then we call it nth root.
In given statement, index is 2 so the answer will be "square root"