AZ-900 Describe cloud concepts Practice Question
A retail company experiences fluctuating customer traffic throughout the year. During peak seasons, traffic can increase by 300% for a few weeks. The company wants to pay only for the compute resources it uses, without needing to invest in permanent infrastructure to handle peak loads. Which cloud computing characteristic best supports this requirement?
⚠ Common exam trap
Many candidates confuse elasticity with high availability, thinking that keeping services running during spikes is the same as scaling resources, but high availability ensures uptime, not dynamic capacity adjustment.
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
✓
Elasticity
Elasticity is the cloud computing characteristic that allows resources to automatically scale up or down based on demand. In this scenario, the retail company needs to handle a 300% traffic spike during peak seasons without permanently provisioning infrastructure, and elasticity enables dynamic provisioning and de-provisioning of compute resources to match the fluctuating load, ensuring they pay only for what they use.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
High availability
Why it's wrong here
High availability ensures an application remains accessible and operational for a high percentage of time, typically defined by an SLA, using techniques like load balancing and redundant deployments across availability sets or regions. It focuses on minimizing downtime and maintaining uptime during failures, not on adjusting capacity in response to demand changes. High availability does not reduce cost by aligning resource usage with fluctuating customer traffic; it instead prioritizes reliability over dynamic cost efficiency.
When this WOULD be correct
A question asks: 'A company needs to ensure its e-commerce website remains operational even if an Azure region fails. Which characteristic is most important?' In that scenario, high availability (often achieved with redundancy across zones) would be the correct answer.
- ✓
Elasticity
Why this is correct
Elasticity is the cloud characteristic that automatically provisions and de-provisions compute resources, such as Azure Virtual Machine Scale Sets or App Service autoscaling, in direct response to real-time demand. This dynamic scaling ensures the retail company pays only for the capacity it actively uses, aligning cost with fluctuating customer traffic. By scaling out during peak hours and scaling in during low traffic, elasticity eliminates the need for over-provisioning and avoids wasted expenditure on idle resources.
- ✗
Fault tolerance
Why it's wrong here
Fault tolerance is the ability of a system to continue operating without interruption when a component fails, often achieved through redundant hardware, software, or design patterns like Azure Availability Zones. This resilience protects against failures but does not respond to changes in customer demand or usage patterns. It does not scale resources up or down to match traffic fluctuations, so it is not the mechanism for avoiding costs of over-provisioning or paying only for used resources.
When this WOULD be correct
A question asking which characteristic ensures a system continues to function despite hardware or software failures, such as 'A company needs its application to remain available even if a server fails. Which cloud characteristic is most important?'
- ✗
Geo-redundancy
Why it's wrong here
Geo-redundancy replicates data and workloads across geographically separate Azure regions to protect against regional disasters and ensure business continuity. This is a data durability and disaster recovery mechanism, not a cost-optimization or resource-scaling feature. While it may involve active-active or active-passive deployments, it does not dynamically adjust resource capacity based on variable customer traffic, nor does it reduce costs by allocating only what is needed at each moment.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The AZ-900 exam frequently reuses these exact scenarios with slightly different constraints.
✓ElasticityCorrect answer▾
Why this is correct
Elasticity is the cloud characteristic that automatically provisions and de-provisions compute resources, such as Azure Virtual Machine Scale Sets or App Service autoscaling, in direct response to real-time demand. This dynamic scaling ensures the retail company pays only for the capacity it actively uses, aligning cost with fluctuating customer traffic. By scaling out during peak hours and scaling in during low traffic, elasticity eliminates the need for over-provisioning and avoids wasted expenditure on idle resources.
✗High availabilityWrong answer — click to see why▾
Why this is wrong here
High availability ensures that applications remain accessible during failures, but it does not enable dynamic scaling of resources based on demand fluctuations. The question focuses on paying only for used resources during traffic spikes, which is a scalability concern, not availability.
★ When this WOULD be the correct answer
A question asks: 'A company needs to ensure its e-commerce website remains operational even if an Azure region fails. Which characteristic is most important?' In that scenario, high availability (often achieved with redundancy across zones) would be the correct answer.
Why candidates choose this
Candidates may confuse high availability with the ability to handle increased load, but high availability is about uptime and fault tolerance, not dynamic resource scaling to match variable demand.
✗Fault toleranceWrong answer — click to see why▾
Why this is wrong here
Fault tolerance ensures system operation during component failures, but does not address scaling compute resources to handle fluctuating demand; it focuses on resilience, not dynamic capacity adjustment.
★ When this WOULD be the correct answer
A question asking which characteristic ensures a system continues to function despite hardware or software failures, such as 'A company needs its application to remain available even if a server fails. Which cloud characteristic is most important?'
Why candidates choose this
Candidates may confuse fault tolerance with elasticity because both relate to handling unexpected conditions, but fault tolerance is about failure recovery, not scaling resources to meet demand changes.
Analysis generated from the official AZ-900blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Go deeper
Related to this question
Learn chapter
What is Cloud Computing?
Key term
Cloud computing
Cloud computing is the on-demand delivery of IT resources over the internet, allowing users to access computing power, storage, and applications without owning physical hardware.
Key term
Elasticity
Elasticity is the ability of a cloud system to automatically add or remove computing resources (like servers, storage, or bandwidth) in response to real-time changes in demand.
About these practice questions
This AZ-900 question is part of Courseiva's 981-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. 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.