1. Basic Structure

A tricycle usually consists of a frame, wheels, steering system, power system (e.g., human-powered, electric, or fuel engine), and seat. The frame is the main structure of the tricycle, which is used to support and connect other parts. The wheels are responsible for traveling, and the steering system enables the tricycle to change direction according to the driver's wishes. The power system provides the energy needed to move the tricycle, and the seat provides a comfortable ride for the driver and passengers.

2.Types

There are various types of tricycles, including but not limited to human-powered tricycles, electric tricycles and fuel tricycles. 

Human-powered tricycles: They are mainly driven by the driver's human power and are usually used for short-distance travel or as urban transportation. They usually have a lightweight body and flexible steering system, making them easy to navigate through the city.

Electric tricycles: using batteries as a power source, they are environmentally friendly, energy efficient and easy to operate. Electric tricycles are usually equipped with recharging equipment that allows the battery to be recharged at night or during free time.

Fuel tricycles: use a fuel engine as a power source and have a higher speed and load capacity. However, they can also produce more noise and pollution.