Questions

The systematic name for a chemical is the unique name given to it by the International Union of Pure Applied Chemistry (IUPAC). The IUPAC name can differ from a chemical compound's general name.

PbO is an ionic compound since it consists of a Lead as metal and Oxygen as nonmetal. The systematic name for PbO is Lead (II) oxide. Here we need to put the (II) since lead has more than one combining capacity.

A constitutional monarchy is a form of monarchical government established under a constitutional system which acknowledges an elected or hereditary monarch as head of state.

The monarchs in a constitutional monarchy had only the power that was allocated to them in the constitution of their land or republic.

In each circle,lower number equals the product of the top two numbers, subtracting 3 for the left hand circle, 4 for the middle, and 5 for the right hand circle.

Our Solution:

They both lied.
The child with the black hair is the girl, and the child with the white hair is the boy.
(If only one lied they would both be boys or both be girls)