Which biome is the richest in terms of animal and plant groups?

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.

Exploration of molecular,genetic and species level diversity for novel products of economic importance is known as

What is the difference between flora, fauna, and vegetation? Eichhornia crassipes is called an exotic species, while Rauwolfia serpentina is an endemic species in India. What do these terms 'exotic' and 'endemic' refer to?

Describe the consumptive use value of biodiversity as food,drugs and medicines,fuel and fiber with possible examples.

Given below are pie diagrams $I$,$II$ and $III$ related to the proportionate number of species of major taxa of invertebrates,vertebrates and plants respectively. Critically study and fill in the blanks $A, B, C$ and $D$.