Answer: how debt effects are considered; i.e. the target debt to value ratio and the level of debt.
Step-by-step explanation:
The Weighted Average Cost of Capital (WACC) values a project by using a discount rate that encompasses all the costs of raising capital. It therefore includes the effects of debt financing in that rate.
Adjusted Present Value (APV) on the other hand, takes the net present value of a project assuming it was solely financed by equity and then adds the present value of the benefits of debt financing such as interest tax shields and costs of debt issuance. Debt is therefore not included in the model like WACC and so considers the effects of debt differently.