EVERYDAY SCIENCE

Detailed explanation-1: -The protonema, which grows directly from the germinating spore, is in most mosses an extensive, branched system of multicellular filaments that are rich in chlorophyll. This stage initiates the accumulation of hormones that influence the further growth of newly formed cells.

Detailed explanation-2: -The predominant stage of the life cycle of a moss (bryophyte) is the gametophyte which consists of two stages. The first stage is the protonema stage, which develops directly from a spore.

Detailed explanation-3: -When a moss first grows from a spore, it starts as a germ tube, which lengthens and branches into a filamentous complex known as a protonema, which develops into a leafy gametophore, the adult form of a gametophyte in bryophytes.

Detailed explanation-4: -Answer. The correct Answer is D. The protonema of moss which is not formed from spore is called 2∘ protonema (it is formed from 1∘ protonema)

Detailed explanation-5: -Protonema of moss and prothallus of Dryopteris is gametophytic.-A sporophyte is a diploid plant structure. It produces spores through asexual division (meiosis). Hence, protonema of moss and prothallus of Dryopteris is not sporophytic.