Explanation
= (Please check the official Docker site for the comprehensive explanation) References: (Some possible references from the web search results are)
* Docker Certified Associate (DCA) Study Guide
* [Docker Certified Associate (DCA) Practice Exam Questions]
* [Docker Certified Associate (DCA) Exam Preparation Guide]
I hope this helps you in your exam preparation. Good luck!

Explanation
Using 'docker service inspect http' does not enable you to view the list of historical tasks for this service. The docker service inspect command shows low-level information about one or more services, such as their configuration, replicas, networks, endpoints, etc. It does not show the history of tasks that have been run by the service. To view the list of historical tasks for this service, you need to use 'docker service ps http'.
References: https://docs.docker.com/engine/reference/commandline/service_inspect/,
https://docs.docker.com/engine/reference/commandline/service_ps/

Explanation
This command will not ensure that overlay traffic between service tasks is encrypted, because it uses an invalid option for enabling encryption and an incomplete option for specifying the network. According to the official documentation, there is no such option as --secure for the docker service create command. The correct option to use is --network <network-name> where <network-name> is an existing overlay network that was created with encryption enabled.
References: https://docs.docker.com/network/drivers/overlay/#encryption
https://docs.docker.com/engine/reference/commandline/service_create/

Explanation
This command does create a swarm service that only listens on port 53 using the UDP protocol. The docker service create command creates a new service in a swarm cluster. The --name flag sets the name of the service.
The -p or --publish flag publishes a port or a range of ports to the swarm. The syntax for publishing a port is -p
<published-port>:<target-port>[/protocol]. The protocol can be tcp or udp. If no protocol is specified, tcp is used by default. In this case, the command publishes port 53 on the swarm and maps it to port 53 in the container using the udp protocol. Therefore, this command creates a swarm service that only listens on port 53 using the udp protocol. References: https://docs.docker.com/engine/reference/commandline/service_create/,
https://docs.docker.com/engine/reference/commandline/service_create/#publish-service-ports-externally-to-the-s