In the cloud responsibility matrix, what three areas is the provider always responsible for in an IaaS environment?

Infrastructure-as-a-service (IaaS) providers are responsible for the underlying infrastructure, including datacenters, networks, and physical hosts. In some cases, they may also be responsible for some operating systems, network controls, applications, and Identity and Access Management (IAM) infrastructure. Customers are always responsible for data and accounts, but may be responsible for applications, network controls, and operating systems as well.