Blockchain integration in IoT is especially beneficial for maintaining data integrity. Blockchain's tamper-proof nature ensures that data remains unaltered, enhancing the trustworthiness of information in IoT applications. Device Availability, Real-time Data Processing, and Energy Efficiency are important but not the primary focus of blockchain integration in IoT.

The integration of IoT in agriculture, where sensors monitor soil moisture and trigger irrigation systems, is an example of Edge Computing. In this scenario, IoT sensors at the "edge" (in the field) collect data, analyze it locally, and make real-time decisions (turning on irrigation) without sending all data to a centralized server. Edge computing enhances efficiency and reduces latency in agriculture applications.

For a medical wearable device requiring immediate response times, an RTOS is the best choice. RTOS is designed to handle real-time applications, making it ideal for critical functions. General-purpose, mobile, and network operating systems may not meet the stringent timing requirements of medical wearables.

Zero-Day attacks target vulnerabilities in IoT devices that are not yet known to the manufacturer or the public. Exploiting these undisclosed weaknesses can lead to unauthorized access or compromise of the device, making it a significant security concern.

FreeRTOS is a real-time operating system (RTOS) kernel that is event-driven and widely used in embedded systems due to its low resource requirements and real-time capabilities.

In advanced IoT applications involving autonomous vehicles and traffic signals, a Publish-Subscribe (Pub/Sub) communication model is most suitable. This model allows multiple devices (vehicles) to publish information (their status, location) to a central hub (traffic signals) and subscribe to updates from others. It's a scalable and efficient way for real-time interaction, enabling vehicles to receive timely traffic information.

In IoT, differential privacy is a technique used to protect the privacy of individual data in a dataset. It adds noise or perturbation to data in a way that makes it challenging to identify individual data points while still allowing useful insights to be derived from the dataset. This is crucial for preserving the privacy of IoT data, especially when dealing with sensitive information.

One of the primary concerns with IoT devices is ensuring interoperability. IoT devices often come from different manufacturers and need to work together seamlessly to provide value. Ensuring that devices can communicate and share data across different platforms and ecosystems is crucial for the success of IoT.

IoT security relies on both authentication, which verifies the identity of the device, and authorization, which specifies what actions the device is allowed to perform. Authorization ensures that devices only perform permitted actions.

A DDoS (Distributed Denial of Service) attack can disrupt the service of an IoT device by overwhelming it with a massive volume of traffic from multiple sources, causing it to become unreachable to legitimate users. DNS, HTTPS, and Malware are not types of attacks but rather components or protocols used in networking and security.