The first stage of primary succession in an ecosystem is the pioneer community.The characteristic feature(s) of a pioneer community is/ are:I.the biomass starts to increase.II.energy consumption is efficient.III.major species are lichens and mosses.

Explanation

The first stage of primary succession involves the establishment of a pioneer community, which is typically composed of species such as lichens and mosses that can colonize bare substrates. These organisms contribute to an increase in biomass by gradually breaking down rocks and accumulating organic material, which paves the way for subsequent communities. While energy consumption is a factor in ecosystems, it is not a distinctive feature of pioneer communities specifically. Hence, options II and its combinations are incorrect.