a) Is e-commerce possible without the Internet? Explain.

No, it is not possible to e-commerce without the internet because the "e" in e-commerce means ELECTRONIC! there is no other way to trade "electronicly" without internet.
b) Describe the 3 forms of e-commerce

3 forms of e-commerce are (B2B): Business to Business which a company handles transactions within its own value chain and with other businesses and organizations.

There is B2C (Business-to-consumer): which represents retail transactions between a company and individual customers.

Lastly, there is C2C (Consumer-to-consumer): this one represents an organization, business or individual thats selling and buying directly with each other through the internet.
c) What are the purposes of an intranet? What are the main characteristics of an intranet?

The purpose of the intranet is to be able to give easy access info to consumers. main characteristics of the intranet are: firewall security for software, network, at least one computer with server software installed, and other computers with client software installed.