Legs of Octopuses

The number of octopus legs is normally eight.
(There is an octopus that has 96 legs.)

We sometimes call them "legs," but most academic books call them "arms" or "tentacles."

Also, I heard that a European study group have researched on octopus legs and arms.

According to the study, it was found that the number of octopus legs is two, and the number of octopus arms is six.

Octopuses use their two backward tentacles to move, and their six forward tentacles to find food or loop up something.

By the way, octopuses have three hearts and nine brains.

タコの足

タコの足は8本とされています。
（中には96本足のタコもいます。）

我々は「足」と呼んでいますが、学術書などでは「腕」と表現されることが多いです。

そして、ヨーロッパの研究グループは、タコの「足」と「腕」について研究をしました。

その結果、タコの足は2本で、腕が6本だということが判明したようです。

タコは最後尾の2本を移動に使い、残りの6本は餌を探したりものを調べたりする際に使うようです。

ちなみに、タコには心臓が3つ、脳が9つあります。

• The number of octopus legs is normally eight.
• Octopuses normally have eight legs.

• We sometimes call them "legs," but most academic books call them "arms" or "tentacles."
• This sentence is perfect! No correction needed!

• Also, I heard that a European study group have researched on octopus legs and arms.
• Also, I heard that a European study group has done research on the arms and legs of octopuses.

• According to the study, it was found that the number of octopus legs is two, and the number of octopus arms is six.
• According to the study, it was found that the octopuses have two legs and six arms.

• Octopuses use their two backward tentacles to move, and their six forward tentacles to find food or loop up something.
• Octopuses use their two backward tentacles to move, and their six forward tentacles to find food or ensnare something.

• By the way, octopuses have three hearts and nine brains.
• This sentence is perfect! No correction needed!

I think it would be more natural to try to avoid "the number of x is y" in this case