W3SVC service and WAS service are the underlining services that needs to be running for IIS to work properly. Without those services IIS will stop running
World Wide Web Publishing Service (W3SVC):
The W3SVC service is the core service responsible for managing websites and web applications hosted on IIS. It listens for incoming HTTP requests, directs them to the appropriate website or application, and handles application pool management.
Windows Process Activation Service (WAS):
WAS is a service responsible for managing IIS application pools. It starts, stops, and monitors application pools, which provide isolation and resource management for web applications.
WAS Ã Windows Process Activation Service (Mandatory Service)
W3SVC Ã World Wide Web Services (W3SVC) For Running www Sites
FTP Ã (FTPSVC) Optional for handling requests from FTP Sites
SMTP Ã (SMTPSVC) Optional for Sending or Receiving Mails
NNTP Ã (NNTPSVC) Optional to Host forums and discussion