A giant pacific octopus have a huge head with 8 legs attch to it, it have pigment cells, tentacles all over it's body, it have 3 hearts; 2 brancial hearts and 1 systemic heart.
there are 289 species of octopus
octopus have 200000 species spiecies
There are around 300 recognized octopus species.
The whole species of octopus is not entirely endangered, but there are some subspecies that are endangered, threatened, or close to being endangered: The Giant Octopus, a giant but gentle octopus, is listed as "Endangered" on the ICUN Redlist.
I think it depends on the type of octopus. I think the most common type of octopus is called the Common Octopus (octopus vulgaris). Hence the name! One of the most venemous types of octopus is the Blue Ringed octopus. If you are looking for a better answer search for 'types of octopuses' and maybe it will tell you which ones are more common.
Octopus bimaculoides
It appears to vary from species to species. For example, Octopus aegina has it; but Octopus vulgaris does not.
Some are but the regular octopus that we buy at the store are not. I hope that helps.:)
Octopus is commonly known as the devil fish. There is no species of that name "Devilfish Octopus". But octopuses have a large variety in sizes as well in species. here is a website with a list of species and their sizes.
There are current 300 recognised species of octopus.
No. Cuttlefish are a different species from octopus
Almost certainly not. Most octopus species are doing well although some may be in some trouble. Check IUCN Redlist.