ANSWER: Both a and b
Explanation:
Scientists have discovered Octlantis - an underwater site built entirely by octopuses, where they communicate with each other by posturing, chasing or colour changes.
Researchers found the site in the waters off the east coast of Australia, that is the home of up to 15 gloomy octopuses.
It is the second gloomy octopus settlement found in the area, and the discovery lends credence to the idea that octopuses are not necessarily loners.
The first gloomy octopus site was found in Jervis Bay off the east coast of Australia in 2009. The new site is located just a few hundred meters away from the first site, and has been dubbed Octlantis.
