In Magento, which property values must be supplied for all types of products without which the products will NOT function?

While configuring the Express Checkout Settings in Magento, suppose you set the 'Billing Agreement Signup' to 'Ask Customer' (marked as A in the image). What does this imply?

Which payment method is NOT available in Magento?

Which is NOT a valid payment action in the Magento backend while setting the PayPal payment method?

By Default, how many Product Tax Classes are included by Magento?

Suppose you want to effect changes to multiple products listed under Manage Products. You select the products and choose an action from the Action dropdown list. Which of the following are NOT valid actions?

Which products do not have a physical presence, and are typically used for such things as services, warranties and subscriptions?

Which file does Magento uses to detect maintenance mode?

The term static view file refers to the following:

Magento URLs are not unique enough to allow caching by URL only.

Which is not a Magento cache type?