Final answer:
A marginal abatement cost curve (MACC) can show the total and optimal costs of pollution reduction and evaluate cost-effectiveness, but it cannot directly show the environmental impact of abatement.
Step-by-step explanation:
From a marginal abatement cost curve (MACC), we can deduce various elements of environmental economics including the total cost of abatement, the optimal level of abatement, and the cost-effectiveness of abatement. However, one aspect that cannot be directly deduced is C. The environmental impact of abatement. The curve indicates the cost of reducing pollution by an additional unit (marginal abatement cost) and how it typically increases as cheaper and easier methods are exhausted. The optimal level of abatement is where the marginal costs equal the marginal benefits. Beyond this point, society is not efficiently allocating resources to pollution reduction as represented by point Qc in the given figure.