The agent count shown in Insights of Log Analytics Workspace

Hi,

i have a few questions in regards to the agent count:

1. what kind of agents will contribute to the count of direct agent, Gateway agents, etc. ? as shown in the page
2. am i right to say that only VMs (i only use VMs so far) will increase the count? regardless of how many agents were installed in a single VM
3. on the Log Analytics Workspace, the Heartbeat query applies to which agent? and will the type/category of the agent be reflected be the same as what it is reflected in the Insights page of LAW?

Below the the screenshot of what i mean by the agent count:

Thanks.