Answer: Option C
Explanation:
A biological species can be defined as the concept which includes the group of individual which lives in one or more population that can reproduce among each other to produce viable species.
Speciation is the phenomenon by which one group of species gets separated from another. The species gets diverge due to reproductive isolation or due to geographical isolation.
Hence, the correct answer is option C
<span>The answer is Haploid spores germinate to give rise to protonema, which later develops into a sporophyte.</span>
A protonema (plural: protonemata) is a
thread-like chain of cells that forms the earliest stage (the haploid phase) of a bryophyte life
cycle..
<span>A haploid gametophyte ( each of whose cells contains a fixed number of
unpaired </span>chromosomes) gives rise to a <span>diploid sporophyte</span>,.
Gametophytes produce haploid sperm and eggs which fuse to form diploid zygotes
that grow into sporophytes.
Oxygen entered the Earth's atmosphere after the appearance of the Great Oxidation Event (Great Oxygenation Event). The Great Oxidation is the first mass extinction on Earth.
The Great Oxidation lasted 2.4 to 2.0 billion years ago.
Oxygen appeared on Earth thanks to cyanobacteria using photosynthesis.
The fossils that provide information on the formation of an oxygen-rich atmosphere are the stromatilites from the Precambrian era. These are layered and columnar fossils consisting mainly of cyanobacteria which were the original life form back then. These bacteria took in carbon dioxide and produced oxygen by photosynthesis as early as 2.5 billion years ago (the earth is about 4.5 billion yrs old).
