Which criterion can be used to measure the number of prokaryotes?

Give the correct descending order of organisms with reference to their estimated number found in the Amazon rainforest:
$(a)$ Plants
$(b)$ Invertebrates
$(c)$ Fishes
$(d)$ Mammals
$(e)$ Birds
Choose the correct answer from the options given below:

Match the following columns regarding the global species diversity of vertebrates and plants:

Column-$I$	Column-$II$
$(P)$ Birds	$(I)$ $12 \%$
$(Q)$ Mammals	$(II)$ $31 \%$
$(R)$ Amphibians	$(III)$ $23 \%$
$(S)$ Gymnosperms	$(IV)$ $32 \%$

According to the world population, India is placed at which position?

Who made a more scientifically sound and globally accepted estimate of global species diversity?

How did ecologists estimate the total number of species on Earth?