Developers can use Visualforce to create a Visualforce page definition. A page definition consists
of two primary elements:
Visualforce markup
A Visualforce controller
Visualforce markup consists of… (Select all that apply)

The markup defines the user interface components that should be included on the page, and the
way they should appear.

What provides access to data that should be displayed in a Visualforce page, and can modify
Visualforce component behavior?

To leverage functionality of Standard Controllers, while simultaneously adding custom logic, you
must write a custom class that extends the standard controller. You notify the Visualforce page of
your customizations via the “extensions” attribute of the <apex:page> tag.

For example, if you use the standard Accounts controller, clicking a Save button in a Visualforce
page results in the same behavior as clicking Save on a standard Account edit page. The same
behavior holds true for Custom objects.