Final answer:
The Metadata Cache is the one that stores object definitions and statistics, helping to speed up databases by caching metadata about the database structure and its objects.
Step-by-step explanation:
The cache that stores object definitions and statistics is known as the Metadata Cache. The Metadata Cache is crucial in systems like databases, where it helps in speeding up the access to metadata information related to the structure of the database, its objects, and their attributes. On the other hand, the Results Cache is designed to store the results of executed queries for faster retrieval upon subsequent requests that match the same query.
The Warehouse Cache generally refers to the storage of processed data in the context of data warehousing, which is not directly related to caching object definitions and statistics.