6. what is the largest mass extinction recorded on earth?

The largest mass extinction ever recorded on earth was that which occurred at the end of the end of the Permian period.

Explanation:

The largest mass extinction of species ever recorded on Earth, which occurred 252 million years ago and eliminated 96% of marine fauna, occurred at the end of the Permian period and was the result of global warming and left the animals of the oceans without sufficient oxygen to survive.

The lack of oxygen caused by global warming explains more than half of the loss of marine diversity in this late Permian mass extinction and other factors, such as acidification or changes in the productivity of photosynthetic organisms, acted as additional causes, according to these scientists.

The situation at the end of the Permian, when the increase of greenhouse gases in the atmosphere generated higher temperatures on Earth, is similar to the current one.

1."lessen the worth of ."

2."increase the worth of."

3." beyond the worth of."

4."against the worth of ."

a and b because with the other three, they simplify to something else.