One of the main challenges in deploying WSN in IoT is the limited battery life of sensor nodes. This is because many sensor nodes are often deployed in remote or inaccessible locations, making it challenging to replace or recharge their batteries.

In a typical IoT system, the Data layer is responsible for processing and analyzing the collected data. This layer is crucial for handling, storing, and making sense of the data gathered from various sensors and devices in the IoT ecosystem.

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.

URLLC in 5G is essential for applications that require extremely low latency, such as autonomous vehicles, where split-second decisions are critical for safety.

One advantage of using predictive analytics in IoT for energy management is reduced energy consumption. By analyzing data from various sensors and devices, predictive analytics can optimize energy usage, helping to reduce energy waste and lower operational costs.