A Looker project typically contains one or more ______________files that contain parameters defining a model and its Explores and joins.

A Looker project typically contains one or more model files that define how data is organized and how it interacts within the Looker environment. These model files are crucial as they outline the relationships between different views, which represent tables in the underlying database. In the models, parameters are set for various elements including Explores, which are the primary means through which users interact with the data, and joins that establish connections between different views. This structure enables users to create complex queries and reports without needing to write SQL directly.

While view, explore, and manifest files play important roles in the Looker architecture, they serve different purposes. View files define the individual data sources and the relationships of fields within a single source, and explore files are a subset of the model that users interact with but do not define the overall relationships and parameters. Manifest files manage project dependencies and settings but do not directly contain the model's parameters or joins. Thus, model files are at the heart of defining how data is structured and queried in Looker, making them essential for any Looker project.