Fog computing is an extension of cloud computing. It extends cloud capabilities to the edge of the network and brings processing closer to the data source. This helps in reducing latency and improving efficiency, making it suitable for IoT and other applications.

Device integrity in IoT pertains to ensuring the trustworthiness of the device's components. This includes verifying that the hardware, software, and data haven't been tampered with, which is essential for maintaining the security of IoT devices.

Python is often recommended for beginners in IoT development due to its simplicity, readability, and extensive libraries like MicroPython and CircuitPython designed for microcontrollers. Klingon, Brainfuck, and Assembly are not suitable for beginners due to their complexity and lack of IoT-specific libraries.

In the realm of IoT, M2M (Machine-to-Machine) communication is when devices autonomously communicate with each other without human intervention. This kind of communication is at the heart of the IoT concept, where devices exchange data and instructions seamlessly.

A smart city using sensors to manage traffic in real-time is an example of M2M (Machine-to-Machine) communication. In this scenario, sensors and machines (traffic management systems) communicate with each other to optimize traffic flow and enhance overall city efficiency without direct human involvement.

Devices that have a predefined lifespan after which they should be decommissioned to ensure network security are following the "End-of-Life" principle. This means that after a certain period, these devices are no longer supported and should be replaced or upgraded to maintain security. This is crucial in preventing vulnerabilities that may arise from outdated or unsupported hardware.

CoAP (Constrained Application Protocol) is designed specifically for IoT scenarios where resources like memory and bandwidth are limited. It's a lightweight and efficient protocol that is well-suited for IoT devices with constrained capabilities. Unlike HTTP and TCP, CoAP is tailored for these resource-constrained environments.

A significant vulnerability in IoT devices is the use of weak or default passwords, which can be exploited by attackers to gain unauthorized access. It's essential to use strong, unique passwords to mitigate this risk.

IoT devices often generate diverse data types, including structured, semi-structured, and unstructured data. NoSQL databases are a suitable choice because they can handle various data types, provide flexibility, and scale horizontally to accommodate the growing data from wearable devices.

Requiring both a password and a biometric scan is a form of Two-Factor Authentication (2FA). It adds an extra layer of security beyond a simple password, making it harder for unauthorized users to gain access.