AZ-900 Describe cloud concepts Practice Question
A company decides to move its email to Microsoft 365. What cloud service model is this an example of?
⚠ Common exam trap
A common mix-up: candidates confuse PaaS with SaaS because both are cloud services, but PaaS is for building and deploying custom applications, whereas SaaS delivers a fully functional application like email.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
SaaS
Moving email to Microsoft 365 is an example of Software as a Service (SaaS) because Microsoft provides the entire email application (Exchange Online) as a fully managed service. The customer accesses the software via a web browser or email client without managing the underlying infrastructure, operating system, or middleware.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
IaaS
Why it's wrong here
IaaS would mean the organization rents foundational cloud resources, such as virtual machines, storage, and networking, and then installs, configures, and maintains its own email server, for example Exchange Server, on those VMs. With Microsoft 365, there is no VM provisioning, no OS patching, and no Exchange installation; Microsoft abstracts all of that away. Therefore, IaaS is incorrect for a fully managed email offering.
- ✗
PaaS
Why it's wrong here
PaaS provides a managed hosting environment where a customer deploys its own application code, while the platform provider handles the underlying servers and scaling. To use email via PaaS, the organization would need to build or install a mail application and then continue to manage application-level settings, authentication, and data. Microsoft 365 email is a fully assembled, ready-to-use product, not an application that the customer deploys onto a managed platform, so PaaS is incorrect.
- ✓
SaaS
Why this is correct
SaaS delivers ready-to-use software over the internet, and the provider owns and manages the complete application stack, including servers, storage, patching, and uptime. Microsoft 365 email, built on Exchange Online, is accessed through Outlook or a web browser, and Microsoft handles redundancy, security updates, and service availability end to end. Because the organization simply consumes the fully managed email application without provisioning anything, SaaS is the correct classification.
- ✗
On-premises
Why it's wrong here
On-premises means the organization owns and operates the mail servers inside its own facilities, covering hardware procurement, power and cooling, OS/Exchange patching, and data backup responsibilities. With Microsoft 365, however, email is hosted in Microsoft's global datacenters and managed by Microsoft itself, with the customer only using the service through a browser or client. This is the direct opposite of an on-premises deployment, so this choice is incorrect.
Go deeper
Related to this question
Learn chapter
What is Cloud Computing?
Key term
SaaS
Software as a Service (SaaS) is a cloud computing model where you use software over the internet without installing it on your own computer.
Key term
Managed service
A managed service is an IT offering where a third-party provider takes full responsibility for maintaining, monitoring, and supporting a specific technology or system on behalf of a customer.
About these practice questions
One of 981 original AZ-900 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AZ-900 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the AZ-900 exam.