Assume that $collection is a new instance of a class that extends
Magento\Framework\Model\ResourceModel\Db\Collection\AbstractCollection, and $ids is an array of ids.
How do you select a list of records from the database where the record ids are in the $ids list?

During a code review of a module MyCompany_PaymentCurrencies you see a configuration field declared in the file etc/adminhtml/system.xml:

What is the consequence of the attribute showInStore being set to 0?

You are setting up a brand new Magento installation for a merchant who is migrating from Magento 1 to Magento 2.
Keeping in mind upgradability and the need to customize, which one do you choose?

\Magento\Sales\Model\Api\OrderRepositoryInterface::getList accepts a SearchCriteriaInterface to filter and sort information.
What class assists in creating an instance for SearchCriteriaInterface?

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?