What characteristics make a community stable?

According to the Rivet Popper Hypothesis,rivets represent $........$.

Which of the following statements are true?
$I$. Species diversity provides stability to the ecosystem.
$II$. Communities with more species tend to be more stable than those with fewer species.
$III$. Ecosystems with higher biodiversity are more productive than ecosystems with lower biodiversity.
$IV$. Biodiversity is not essential for the maintenance and health of the ecosystem.
Choose the correct option.

David Tilman suggested:

Identify the incorrect statement regarding the stability of a biological community.

$...............$ found that plots with more species showed less year-to-year variation in total biomass. Increased diversity contributes to higher productivity.