Wearable devices primarily use the "Bluetooth" communication model to send health metrics and data to the user's smartphone or other devices. Bluetooth is a short-range wireless communication technology commonly used in wearables for connectivity.

A temperature sensor would be the most appropriate choice for monitoring the shipment of perishable goods. Temperature sensors, often referred to as thermometers or thermocouples, measure the temperature of their surroundings. In this context, they are crucial for ensuring that perishable items remain within a safe temperature range during transportation, such as in refrigerated trucks or containers.

Data analytics in IoT is instrumental in gaining insights from the vast amount of data generated by IoT devices. It helps in detecting anomalies, predicting trends, and making informed decisions, which are essential for optimizing operations and achieving the goals of IoT applications.

By the year 2015, the number of connected devices had already surpassed the global human population. This milestone highlights the rapid growth of IoT, where everyday objects and devices are becoming smart and interconnected, contributing to the data-driven world we live in today.

The primary purpose of IoT data collection is data analysis and decision-making. IoT devices collect vast amounts of data, which is then processed and analyzed to derive insights and make informed decisions. This data can be used for various applications, including predictive maintenance, improving efficiency, and enhancing user experiences.

In this scenario, the primary requirement is real-time analysis of immense data generated by thousands of sensors. Edge computing is the best technology for this purpose, as it allows data processing to occur closer to the data source, reducing latency and enabling real-time analytics, which is crucial in monitoring traffic patterns in a smart city.

The term "Internet of Things" (IoT) was first coined by Kevin Ashton, a British technology pioneer and entrepreneur. He used this term in a presentation he made at Procter & Gamble in 1999 to describe the concept of connecting physical objects to the internet.

Blockchain is often used in IoT to ensure data privacy during transmission. Blockchain technology provides a secure and tamper-proof way to record and transmit data, making it an excellent choice for maintaining the integrity and security of IoT data during transmission.

The part of the IoT architecture that interacts with the physical world and has sensors and actuators is called the "Device" layer. This is where the IoT sensors and actuators are located, collecting and controlling physical data and processes.

To extend the battery life of IoT devices, it is crucial to implement power-efficient techniques. Deep sleep modes, where the device is put into a low-power state and periodically wakes up to perform tasks, are most appropriate for conserving battery power. Frequent data transmission and continuous high-power modes consume more energy and are not suitable for devices with extended battery life requirements.