Explanation
https://docs.paloaltonetworks.com/pan-os/9-1/pan-os-web-interface-help/device/device-certificate-management-c

Explanation
URL filtering is a feature in Palo Alto Networks firewalls that allows administrators to block access to specific URLs [1]. This feature can be configured via four different objects: Custom URL categories in URL Filtering profiles, PAN-DB URL categories in URL Filtering profiles, External Dynamic Lists (EDL) in URL Filtering profiles, and Custom URL categories in Security policy rules. The evaluation order for URL filtering is:
Custom URL categories in URL Filtering profile, PAN-DB URL categories in URL Filtering profile, EDL in URL Filtering profile, and Custom URL category in Security policy rule. This information can be found in the Palo Alto Networks PCNSE Study Guide, which can be accessed here:
https://www.paloaltonetworks.com/documentation/80/pan-os/pan-os/resource-library/palo-alto-networks-pcnse-s

Explanation
According to the Palo Alto Networks Knowledge Base12, the best definition of the Heartbeat Interval is A.
The interval in milliseconds between hello packets.
The Heartbeat Interval is a CLI command that configures how often an HA peer sends an ICMP ping to its partner through the HA control link. The ping verifies network connectivity and ensures that the peer kernel is responsive. The default value is 1000ms for all Palo Alto Networks platforms.

Explanation
https://docs.paloaltonetworks.com/pan-os/10-0/pan-os-admin/policy/security-profiles.html First note in above link states:
"Security profiles are not used in the match criteria of a traffic flow. The security profile is applied to scan traffic after the application or category is allowed by the security policy." The first thing the firewall checks per it's flow is the security policy match and action. The Security Profile never gets checked if a match happens on a policy set to deny that match.

Explanation
https://docs.paloaltonetworks.com/sd-wan/1-0/sd-wan-admin/sd-wan-overview/plan-sd-wan-configuration