How the breadboard pins are connected internally ? There is not an single use of breadboard given
When you will hold the breadboard as shown below, all the vertical pins below the separating line are internally connected and above the separating line are internally connected respectively as marked in the figure. No two horizontal pins have internally connected to each other.
It is advisable to use whenever we are including more than one electronic component in our connections to avoid chance short circuits and loose connections.
Like in this picture if the resistor leg touches the LDR leg then there will be short circuit which may damage the whole board. So, I would discourage this type of connections without the use of breadboard.