Final answer:
Custom software is designed for specific applications and a software developer works in the quaternary sector of an economy, focusing on information technology and knowledge-based services.
Step-by-step explanation:
Software that is tailor-made for special applications is referred to as custom software. These programs are designed specifically to meet the unique requirements of a particular business or user, as opposed to generic or off-the-shelf software that is made for a broad audience with standard features. Custom software is often created by software developers to address the specific needs that can't be met by existing commercial software.
In response to the second question, a software developer would typically work in the quaternary sector of an economy, which includes services such as information technology, research and development, and other forms of knowledge-based services. This sector is characterized by the creation and transfer of information and the development of new ideas and technologies.