What is the difference between a manual address lease and a dynamic address lease?

What will be an ideal response?

With a manual address lease, the administrator explicitly assigns an IP address manually by associating a client's hardware address with a specific IP address to be leased to that client. Use this type of address lease if you want DHCP to manage all IP addresses, but you also want to control some address assignments directly.
Dynamic: The DHCP server assigns addresses for specific periods of time. Use a dynamic address lease to assign addresses to clients or other machines when fixed IP addresses are not required. Given the prevalence of clients on most networks, this is the most prevalent type of DHCP address lease. Dynamic address leases come from the dynamic address pool, and represent those addresses not already reserved for static allocation.