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Description and function of stomata:

• Stomata are kidney shaped structures that appears on the leaves of plants.
• The kidney shaped cells are called guard cell which functions are regulators by increasing and decreasing their size.
• The function of stomata includes exchange of gases and transpiration.
• In day time stomata helps the leaves to take in CO2 for photosynthesis while releasing oxygen and at night its vice-versa.
• Transpiration is the evaporation of water from leaf surface.

Explanation why mosses possess stomata:

• The bryophytes are divided into Mosses, Liverworts and Hornworts.
• Mosses are terrestrial plants that bear spores and are non vascular.
• The mosses are the first group of plants to bear stomata.
• Although all mosses do not have stomata and the stomata are present in the stem of the sporophyte instead of leaves.
• The sporophyte of a moss is the asexual body which has a spore containing capsule.

Hence, option (d) is correct.

• Charales and Liverworts do not possess stomata.
• Stomata appears in Hornworts as scattered cells in the spopophyte but hornworts are not the first group to possess stomata.