You are working on a jewelry store that sells rings. Each ring allows an adjustment in size. The customer specifies finger size in inches and the merchant physically adjusts the stocked ring to the required size.
How is this represented in Magento?

In a code review of a merchant's site you have discovered that there are multiple observers for the checkout_submit_all_after event. After closer inspection, you notice one of these observers is relying on the others being executed before it is called.
What risk does this pose, and how can it be mitigated?

You have created a new section in system configuration under the Catalog tab:

How do you restrict an access to the section using Magento ACL?

You need to find all orders in the processing state. You have written the code:

How do you resolve the exception?

Magento allows you to specify custom values per store for product attributes created in the admin panel.
Which architectural pattern makes it possible?