Two factors contributed to the success of the pteridophytes: the extreme miniaturization of the gametophytic generation and an important development of the sporophytic generation (development of the tree forms).
Pteridophytes are a group of plants that peaked in the Carboniferous (-300 million years). It is the first great terrestrial plant civilization. These plants would have appeared in the Devonian -400 million years ago, perhaps from certain primitive terrestrial plants which, unlike bryophytes, would have favored the diploid generation on the haploid generation.
Particularly well adapted to terrestrial life, they have created, thanks to the development of tree forms, immense forests whose fossilization is at the origin of coal deposits.
Pteridophytes are at the origin of an evolutionary lineage based on the extreme miniaturization of gametophytic generation and an important development of sporophytic generation, leading to all tracheophytes including current flowering plants. Pteridophytes are well adapted to terrestrial life, however fertilization still requires the presence of water since male gametes are swimmers.
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Water is less dense as a solid than as a liquid the answer is D
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<h3><u>Answer;</u></h3>
A. <em>18 hydrogen atoms </em>
<h3><u>Explanation;</u></h3>
- <em><u>Alkanes are group of hydrocarbon that are saturated</u></em>. They are saturated in the sense that each carbon atom has maximum number of hydrogen atoms.
- <em><u>The homologous series of alkanes has a general formula of CₓH₂ₓ₊₂.</u></em>
- Therefore,<u><em> an alkane with 8 carbons will have; (2×8) +2 = 18 hydrogen atoms. </em></u>Thus, the formula of the hyrocarbon will be; C₈H₁₈.