What is the estimated number of species of organisms on Earth?

Animals account for more than $P$ of all species recorded. Even if we combine all plant species (algae,fungi,bryophytes,gymnosperms,and angiosperms),they account for no more than $Q$ of the total percentage.

Approximately how many varieties of rice are found in India?

Select the option that represents the organisms in ascending order of their species richness.

According to Robert May's global estimates,what percentage of the total species on Earth has been discovered so far (in $\%$)?

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