Which tool can deploy destructive changes to Apex classes in production?

Consider the following code snippet:

Given the multi-tenant architecture of the Salesforce platform, what Is a best practice a developer should Implement and ensure successful execution of the method?

Application Events follow the traditional publish-subscribe model. Which method is used to fire an event?

code below deserializes input into a list of Accounts.

Which code modification should be made to insert the Accounts so that field-level security is respected?

When a task is created for a contact, how can a developer prevent the task from being included on the activity timeline of the contact's account record?