Final answer:
The attribute specifying the number of dependencies between two software units is the 'dependency ratio'. It is used to assess software complexity and is not directly related to downloads or media usage.
Step-by-step explanation:
The attribute that specifies the number of dependencies between two units of software is often referred to as the dependency ratio. This measure can help in understanding the complexity of a software system, indicating how changes in one unit may affect other units. To quantify the dependency ratio, we might create an equation or metric based on specific criteria, such as the number of function calls, shared data, or other interfacing elements between software modules.For instance, if we take the number of songs downloaded and the number of times each song is used in movies as dependencies, we might construct an equation based on these variables to analyze the relationship. However, the given context seems to be unrelated to the concept of dependencies in software, possibly suggesting confusion or a mix-up in the question. In software engineering, dependencies would involve the relationships between components, not the usage metrics like song downloads or movie appearances.