1. Power Apps is a low-code app development tool from Microsoft that allows users to easily create apps for mobile, tablets and PCs by combining pre-built components without extensive coding. 2. C# is a programming language developed by Microsoft that can be used to create more complex apps and solutions as it involves writing code. 3. The presenter created a simple app called "Chomanize" using Power Apps and a C# web API to demonstrate how these two tools can be connected, with Power Apps providing a simple and fast interface and C# enabling more complex functionality through programming.