Cells<span> are the basic unit of structure and function in all living things. Hope this helps. :)</span>
Seamount and guyot are types of mountain - so we can reject those options, since we're looking for a flat surface, not a mountain.
A trench is a narrow ditch, or depression so also it's not a plain
The correct answer is abyssal plain - it's a plain typically next to a continental rise (leading to the continent) and a mid-ocean ridge.
I think the answer is C, but it is hard to tell because it seems incomplete.
I think the correct answer from the choices listed above is option A. The <span>type of mutation that would convert a proto-oncogene into an oncogene would be </span><span>a deletion of most of the proto-oncogene coding sequence. Hope this answers the question. Have a nice day.</span>