What is the difference between flagella and cilia in terms of their structure and function?

Flagella and cilia are both hair-like structures found on cells, but they differ in size and function. Flagella are longer and fewer in number, while cilia are shorter and more numerous. Flagella typically help with cell movement, such as propelling sperm, while cilia are involved in moving substances along the cell surface, like in the respiratory tract to clear mucus.