Hello There!
It is from adult bone marrow.
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- Hannah ❤
Both seta and cheta or chaete means bristles. I think the term can be used interchangeably . Just check this link:- http://en.wikipedia.org/wiki/Polychaete It about polychaetes a class of annelid worms. These are extracts form the passage:- Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called *chaetae, which are made of chitin. Indeed, polychaetes are sometimes referred to as bristle worms. Bundles of bristles, called *setae, project from the parapodia. http://en.wikipedia.org/wiki/File:Polychaeta_anatomy_en.svg Thats a cross section the terms have been used interchangebly.
Answer:
The answer is A
Explanation:
Since their variations are best suited for the environment, they have a higher chance of surviving.
