Kindly assist, I'm being challenged.

4.4. In general, and in terms of short-run and long-run elasticities, why do short-run demand and supply curves look very different from their long-run counterparts? Explain and indicate which period is seen as short run and which as long run. 4.5. If two products are substitutes, what must the magnitude of the cross-price elasticity of demand be (i.e. negative, positive, zero or infinite)? 4.6. Consider two goods, A and B. The price of product A increases from R6 to R8 per unit. As a result, the quantity demanded of product B decreases from 200 to 190 units. 4.6.1. Given the information above, calculate the cross-price elasticity of demand using the midpoint (are) formula. 4.6.2. Are goods A and B substitutes or complements? 4.6.3. Give two real-world examples of goods such as A and B