Which SOQL query successfully returns the Accounts grouped by name?

How should a developer make sure that a child record on a custom object, with a lookup to the Account object, has the same sharing access as its associated account?

Which one do you like?
What should a developer consider for an environment that has over 10,000 Case records?

A change set deployment from a sandbox to production fails due to a failure in a managed package unit test.
The developer spoke with the manager package owner and they determined it is a false positive and can be ignored. What should the developer do to successfully deploy?

Which action can a developer take to reduce the execution time of the following code? List<account> allaccounts = [select id from account]; list<account> allcontacts = [select id, accountid from contact]; for (account a :allaccounts){ for (contact c:allcontacts){ if(c.accountid = a.id){ //do work } } }