Explanation:

Let's analyze each application in the context of Microsoft Azure AI Fundamentals (AI-900) and computer vision model types.
* App1 - Uses a set of images of tumors to identify whether the tumors are benign or malignant and suggest a treatment # Image classificationThis application is performing image classification, where each image (of a tumor) is assigned to a single predefined category - benign or malignant. Image classification models learn patterns from labeled training images and predict the correct class for new ones. In this case, the model identifies the type of tumor, a classic binary classification scenario.
* App2 - Uses images from cameras to track individual livestock as they move around a farm # Object detectionThis scenario describes object detection, which not only identifies what objects (in this case, animals) are in an image but also locates them by drawing bounding boxes. Tracking movement requires detecting the position of each animal frame by frame. Object detection models are well-suited for use cases involving counting, tracking, or monitoring objects in a visual scene.
* App3 - Identifies brands in photographs of billboards # Optical character recognition (OCR)This app involves reading and interpreting text (brand names, slogans, or logos) from images of billboards.
Optical Character Recognition (OCR), part of Azure AI Vision, extracts textual information from images or scanned documents. Once extracted, that text can be analyzed to identify brand names or keywords.
Summary:
* App1 # Image classification
* App2 # Object detection
* App3 # Optical character recognition (OCR)