Parts of Speech 5

Harmful microorganisms in humans are known, but little is said about dangerous bacteria in meat and fish. What describes the amount of information?

Harmful microorganisms in humans vs. dangerous bacteria in meat and fish.

There is plenty of information about harmful microorganisms in humans, but little is said about dangerous bacteria in meat and fish.

Harmful microorganisms in humans vs. dangerous ___ in meat and fish.

Harmful microorganisms exist in us humans, but little is known about dangerous bacteria in meat and fish.

Harmful microorganisms in humans are well-documented, but little has been ___ about dangerous bacteria in meat and fish.

Harmful microorganisms exist in humans, but little is said about dangerous bacteria ___ in meat and fish.

Harmful microorganisms are found inside humans, but little is said about dangerous bacteria in meat and fish.

Harmful microorganisms in humans are well-documented, but little is said about dangerous bacteria in meat and fish products, ___ not much has been said.

Harmful microorganisms exist in humans, but little is said about dangerous bacteria in meat and fish products. What type of word is 'has been'?