Observe the global biodiversity distribution of the major plant

Observe the global biodiversity distribution of the major plant taxa in the given diagram and answer the questions accordingly.
observe-the-global-biodiversity-distribution-of-the-major-plant-1
(i) Which group of plants are the most endangered?
(ii) Why are mosses/fems so few? Give reason.
(iii) How do fungi that are heterotrophs sustain themselves as a large population?
(iv) Which group of plants is most advanced and which one is most primitive?

(i) Lichens.
(ii) Mosses and ferns are very few as they need humid conditions in forests and forests are disappearing.
(iii) Fungi are able to sustain themselves as a large population because of their wider adaptability to the changing environment conditions.
(iv) Most advanced group is of angiosperms and most primitive group is of fungi.