Update units/en/unit1/key-concepts.mdx

Author: burtenshaw

units/en/unit1/key-concepts.mdx

@@ -78,7 +78,7 @@ In the following diagram, we can see the collective capabilities applied to a us
 
 ![collective diagram](https://huggingface.co/datasets/mcp-course/images/resolve/main/unit1/8.png)
 
-This application might use the MCP entities in the following way:
+This application might use their MCP entities in the following way:
 
 | Entity | Name | Description |
 | --- | --- | --- |