$1.)$ The three most popular B$2$B marketplaces are Alibaba, Amazon Business and Thomas Net. Alibaba is one of the biggest leaders globally in e$-$commerce, it connects millions of buyers and suppliers around the world. It offers a wide range of products across various categories, electronics, machinery and some apparel. The companies$$ practices include secure payment, trade assurance, and comprehensive supplier verification processes. An advantage is streamlining transactions.

Amazon business is an extension of the retail platform, specifically made for business customers. You can get bulk purchasing options, and business only prices. You can get muti user accounts, and integration with procurement systems. Its advantage is vast product selection and a customer centric approach.

The last one is Thomas Net, it is a big leader in industrial and manufacturing business in America. It connects buyers with industrial buyers. They mainly use CAD drawings and product catalogs. It also offers marketing and advertising services for its suppliers. The E$-$commerce makes the advantages with supplier discovery and enhancing transparency

$2.)$ Two cloud based storage systems are google drive and dropbox. Google drive offers $15$ GB of free storage. Annual costs is $19\mathrm{.}99$ for $100$gb and $10$ dollars for each $10$gb of storage. Its advantages include integration with google workspace and easy sharing. The disadvantage is the limited free storage compared to some of the competitors.

Dropbox offers $2$ gb of free storage. The annual cost is $$119\mathrm{.}88$ for $2$ tb of storage. The user$-$friendly interface, and strong file synchronization capabilities is the advantages. The disadvantages are the less free storage space and the higher costs for additional storage compared to most competitors.