The Chondrichthyes are the cartilaginous fishes including the sharks, rays,<span>skates and chimeras. The Osteichthyes are the bony fish. Both of these groups </span>became established during the Devonian Period about 400 million years ago. The Chondrichthyes <span>differ from the Osteichthyes in many respects, including their</span><span>
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<span>284 km in 2 million years.</span>
Answer: B. Earth's present-day species evolved from older, identical species.
The evolution is the change or modification in the characteristics of a species over genration due to the process of adaptation and natural selection. The statement "Earth's present day species evolved from older, identical species is true about evolution". As, proposed by Darwin evolution is "descent with modification", which means that in a process of evolution species change and give rise to new species over generation. He proposed that newly evolved life forms can be traced back to their common ancestor.