Final answer:
Demand and supply depend on external factors and are represented by shifts in their respective curves caused by various economic influences, not directly by a change in product price.
Step-by-step explanation:
The true statement about demand and supply is that they depend on external factors. The relationship between demand and supply is best understood within the context of the ceteris paribus assumption, meaning 'other things being equal.' When analyzing supply and demand, it's important to note that while the curves typically represent the relationship between price and quantity, they are influenced by a variety of external factors. These can cause the curves to shift, indicating a change in demand or supply not caused by a change in the product's price.
The seven factors that may cause a change in supply include the cost of inputs, productivity, new technology, taxes, subsidies, expectations, government regulations, and the number of sellers in the market. Supply and demand are not directly nor inversely related but are influenced by a wide range of economic factors.