In systems theory and information processing, inputs are often classified into two categories that enter a system: which pair correctly names these input types?

Introduction / Context:
General systems theory distinguishes the kinds of inputs a system receives. Understanding these categories helps analysts design controls, resource provisioning, and monitoring that match the nature of the input stream and the system’s purpose.

Given Data / Assumptions:

• We consider conceptual input classes, not physical media.
• One class maintains system viability; the other conveys information to be processed.
• Outputs are distinct (products, services, or waste).

Concept / Approach:

Maintenance inputs sustain the system’s operation (resources such as energy, staffing, budget, and supplies). Signal inputs carry information to be transformed (transactions, messages, sensor readings). Clear separation clarifies which inputs are necessary to run the system and which are the subject of processing.

Step-by-Step Solution:

Verification / Alternative check:

Systems analysis texts consistently present this dichotomy to frame data collection and resource planning.

Why Other Options Are Wrong:

Products/waste are outputs, not inputs.

“Energies and maintenance” overlaps partially but omits the information-bearing signal category.

“Maintenance and waste” mixes input with output.

Common Pitfalls:

Conflating throughput resources (like CPU time) with information inputs; both are needed but serve different roles in design and capacity planning.

Final Answer:

maintenance and signal