With the aid of an appropriate diagram state and explain the law of demand.

The Law of Demand states that, ceteris paribus (all other factors being constant), as the price of a good or service increases, the quantity demanded for that good or service decreases, and vice versa. This inverse relationship means that consumers will buy less of a product when its price is high and more when its price is low.

Here is an appropriate diagram illustrating the law of demand:

\begin{tikzpicture} \draw[->] (0,0) -- (5,0) node[right] {Quantity Demanded (Q)}; \draw[->] (0,0) -- (0,5) node[above] {Price (P)}; \draw[thick, blue] (1,4) -- (4,1) node[below right] {Demand Curve (D)}; \node at (0,-0.2) {0}; \draw[dashed] (0,4) -- (1,4) -- (1,0); \node at (-0.3,4) {$P_1$}; \node at (1,-0.3) {$Q_1$}; \draw[dashed] (0,1) -- (4,1) -- (4,0); \node at (-0.3,1) {$P_2$}; \node at (4,-0.3) {$Q_2$}; \end{tikzpicture}

Explanation of the Diagram:
The diagram shows a downward-sloping demand curve (D).

• When the price is high ($P_1$), the quantity demanded is low ($Q_1$).
• When the price decreases to $P_2$, the quantity demanded increases to $Q_2$. This movement along the demand curve visually represents the inverse relationship between price and quantity demanded, which is the essence of the law of demand.