Define the following terms:
$1$. Biodiversity
$2$. Species diversity

Tropical regions show the greatest level of species richness because:
$A$. Tropical latitudes have remained relatively undisturbed for millions of years,hence more time was available for species diversification.
$B$. Tropical environments are more seasonal.
$C$. More solar energy is available in the tropics.
$D$. Constant environments promote niche specialization.
$E$. Tropical environments are constant and predictable.
Choose the correct answer from the options given below.

Which of the following statements is correct?

Species richness is maximum:

Where is $70\%$ of the world's total freshwater found?

In the $Rivet$ $Popper$ hypothesis,what do the rivets represent?