Questions

The four main functions of a computer are ::

1. Input,

2. Processing,

3. Output and

4. Storage

A search engine is a information retrieval program that constantly collects information on the Web, following links in Web sites and reading Web pages. The search results are presented in a list format and are called as hits.

A metasearch engine is a search tool that uses another search engine's data to produce its own results from the Internet. These engines take input from a user and simultaneously send out queries to third party search engines for results. It searches other search engines rather than individual Web sites.

Examples of Metasearch engine includes - Dogpile, Zoo, Yabado, Metager, etc...

The logic in the given puzzle is 

4 + 4 = 4 * 4+1 = 4 * 5 = 20

5 + 5 = 5 * 5+1 = 5 * 6 = 30

6 + 6 = 6 * 6+1 = 6 * 7 = 42

7 + 7 = 7 * 7+1 = 7 * 8 = 56

Similarly

9 + 9 = 9 * 9+1 = 9 * 10 = 90.

Oxygen is the final electron acceptor of cellular respiration.