Explanation
* The Definition of Done is a formal description of the state of the Increment when it meets the quality measures required for the product. The Definition of Done is used to assess when work is complete on the product Increment.
* The Definition of Done is defined by the Scrum Team, not by the Product Owner alone. The Scrum Team consists of one Product Owner, one Scrum Master, and Developers. They are all accountable for creating a valuable, useful, and potentially releasable product Increment each Sprint.
* The Product Owner is accountable for maximizing the value of the product resulting from the work of the Scrum Team. The Product Owner is responsible for managing and refining the Product Backlog, collaborating with the stakeholders and the Developers, and ordering the items in a way that best achieves goals and missions. The Product Owner represents the interests of everyone with a stake in the product and ensures that the Scrum Team works on the right things at the right time.
* The Developers are accountable for creating a "Done" Increment that meets the Definition of Done each Sprint. The Developers are responsible for planning and executing the Sprint Backlog, designing and building the product functionality, testing and improving the product quality, and delivering a potentially releasable Increment. The Developers work closely with the Product Owner to understand
* and clarify the Product Backlog items, provide feedback and estimates, and suggest improvements and innovations.
* The Scrum Master is accountable for establishing Scrum as defined in the Scrum Guide. The Scrum Master is responsible for promoting and supporting Scrum as defined in the Scrum Guide. The Scrum Master does this by helping everyone understand Scrum theory and practice, both within the Scrum Team and the organization.
* The Definition of Done may vary from one Scrum Team to another, depending on the context and domain of work. However, it must be consistent within one team. If there are multiple Scrum Teams working on one product, they must share a common Definition of Done. If there is an organizational standard for a Definition of Done, all Scrum Teams must follow it as a minimum.
References:
* Scrum Guide: https://www.scrumguides.org/scrum-guide.html
* Definition of Done: https://www.scrum.org/resources/what-is-a-definition-of-done
* Product Owner: https://www.scrum.org/resources/what-is-a-product-owner
* Developers: https://www.scrum.org/resources/what-is-a-developer-in-scrum
* Scrum Master: https://www.scrum.org/resources/what-is-a-scrum-master

* The Sprint Review is an event that occurs at the end of each Sprint, where the Scrum Team and the stakeholders inspect the Increment and adapt the Product Backlog if needed. The Sprint Review is an opportunity for the Product Owner to validate that the Increment meets their expectations and delivers value to the customers and users. The Sprint Review is also an opportunity for the Developers to demonstrate their work and receive feedback from the Product Owner and the stakeholders.
* Stakeholders are people external to the Scrum Team who have a stake or interest in the product, such as customers, users, sponsors, managers, or other teams. Stakeholders provide valuable input, feedback, and insights to the Scrum Team regarding the product vision, goals, value proposition, requirements, features, functions, quality, usability, or market conditions.
* Collecting stakeholder feedback is one of the main purposes of the Sprint Review. Stakeholder feedback can help the Scrum Team to:
* Assess the value and quality of the product Increment and identify any gaps or issues that need to be addressed.
* Understand the needs and expectations of the customers and users and discover new opportunities or ideas for improvement or innovation.
* Align and collaborate with the stakeholders on the product direction and priorities and ensure transparency and trust.
* Adapt the Product Backlog based on the feedback and data and plan for the next Sprint.
References:
* Scrum Guide: https://www.scrumguides.org/scrum-guide.html
* Sprint Review: https://www.scrum.org/resources/what-is-a-sprint-review
* Stakeholders: https://www.agilealliance.org/glossary/stakeholders

Cross-functional teams are not optimized to work on one component or layer of a system only. This is because:
* Cross-functional teams are teams that have all the skills and competencies needed to accomplish the work without depending on others who are not part of the team.
* Cross-functional teams are able to deliver value across the entire product, rather than focusing on a specific component or layer. They can work on any aspect of the product that is needed to achieve the Sprint Goal and the Product Goal.
* Cross-functional teams are more agile, collaborative, and creative than teams that are specialized or siloed. They can reduce dependencies, handoffs, and delays, and increase feedback, learning, and adaptation.
References:
* [Scrum Guide], page 7, section "Developers"
* [Scrum Guide], page 10, section "Product Goal"
* [Scrum Guide], page 7, section "The Scrum Team"

The Daily Scrum is a 15-minute event for the Developers to inspect their progress toward the Sprint Goal and adapt the Sprint Backlog as necessary1. It is a key opportunity for the Developers to plan their work for the next 24 hours and collaborate on any challenges or impediments2. If the frequency of the Daily Scrum were to be lowered to every two or three days, three key concerns would be:
The Sprint Backlog may become inaccurate. The Sprint Backlog is the plan for how the Developers will achieve the Sprint Goal, and it is updated throughout the Sprint as more is learned[3][3] . The Daily Scrum is a chance for the Developers to inspect the Sprint Backlog and make adjustments based on the current situation4. If the Daily Scrum is less frequent, the Sprint Backlog may not reflect the reality of the work, and the Developers may lose track of their progress and alignment with the Sprint Goal.
Opportunities to inspect and adapt the Sprint Backlog are lost. Scrum is based on empiricism, which means that knowledge comes from experience and making decisions based on what is observed5. The Daily Scrum is an essential event for the Developers to apply empiricism to their work, by inspecting the Sprint Backlog and adapting it to optimize the value and quality of the Increment. If the Daily Scrum is less frequent, the Developers may miss opportunities to inspect and adapt their work, and may not be able to deliver a valuable, useful Increment every Sprint.
Impediments are raised and resolved more slowly. An impediment is anything that prevents the Scrum Team from delivering a product Increment. The Daily Scrum is a forum for the Developers to identify and communicate any impediments that affect their work, and to seek help from the Scrum Master or other team members. If the Daily Scrum is less frequent, the impediments may not be raised and resolved in a timely manner, and may cause delays or quality issues in the product delivery.
References:
1: The Scrum Guide, November 2020, p. 10
2: The Scrum Guide, November 2020, p. 11
[3][3] : The Scrum Guide, November 2020, p. 10
4: Understanding and Applying the Scrum Framework, Scrum.org, accessed on December 16, 2023
5: The Scrum Guide, November 2020, p. 4
6: The Scrum Guide, November 2020, p. 11
7: The Scrum Guide, November 2020, p. 14
8: Developing People and Teams, Scrum.org, accessed on December 16, 2023