Equation 5d typically includes several key parameters: - Susceptible Individuals (S): The number of people who are at risk of contracting the disease. - Infected Individuals (I): The number of people who have contracted the disease and can transmit it to others. - Recovered Individuals (R): The number of people who have recovered from the disease and are assumed to be immune. - Transmission Rate (β): The rate at which the disease spreads from infected to susceptible individuals. - Recovery Rate (γ): The rate at which infected individuals recover and move to the recovered category.