The following pie chart represents the global biodiversity of invertebrates. Identify the group of Molluscs from the given labels.

Alexander von Humboldt described for the first time

Assertion : Diversity observed in the entire geographical area is called gamma diversity.
Reason : Biodiversity decreases from high altitude to low altitude.

Biodiversity refers to ......

Within a region,species richness increases with an increasing explored area,but only up to a limit. Which naturalist proposed this statement?

Give scientific reasons: It is difficult to estimate global diversity for prokaryotes.