Final answer:
The 'number of features' describes the different characteristics of a system that can be used for classification and understanding of its functionality. Requirements signify conditions that a system must meet, while constraints are limitations on the system's design.
Step-by-step explanation:
The term number of features refers to the various aspects or characteristics that can be used to distinguish and classify entities within a system. In the context of systems engineering, a feature might pertain to the specific functionality, capabilities, or aspects of the system's design to satisfy exact user requirements. For example, when considering a group of organisms or objects, one may look at features such as size or color which allow for easy classification, especially when there are clear distinctions or 'gaps' in their distribution. A system, as defined in Essential Knowledge 1.A.1, is an object or collection of objects without internal structure, so the number of features provides a way to understand and categorize the complexity of this collection.
Requirements are conditions that the system must meet, like water purity or a certain production rate in a water treatment system. Constraints, on the other hand, represent limitations to the design process, such as budget or environmental regulations.
Moreover, any detailed design considers both the quantitative and qualitative aspects. These include not only the shapes and dimensions, which are quantifiable, but also market analysis which evaluates the product's potential against consumer needs and competition. Correct use of quantification is critical, with numerical representations related always to the appropriate unit to communicate the information effectively, as seen in the principle that quantities combine both a number and a unit.