Final answer:
The two fundamental qualitative characteristics that make accounting information decision-useful according to the FASB's conceptual framework are relevance and faithful representation, ensuring the information is useful and reliable.
Step-by-step explanation:
According to the FASB's conceptual framework, the two fundamental qualitative characteristics that make accounting information useful for decision-making are relevance and faithful representation. Relevance means that the accounting information must be capable of making a difference in a decision by helping users to form predictions about the outcomes of past, present, and future events or to confirm or correct prior expectations. Faithful representation means that the information reflects the economic substance of business events and not merely their legal form, is complete, neutral, and free from material error. Both characteristics are essential for accounting information to be useful, as they ensure that the information is highly adaptable, easy to interpret, and can communicate the reality of large scale processes effectively, thereby distinguishing fact from opinion.