Answer:
Carbon atoms
Explanation:
Mass no. of an element= no. of protons + no. of neutrons = 6 + 7 = 13
Atomic no. = no. of protons/electrons = 6
There is an unbalanced situation between the neutron no and proton no. so this has to be an isotope of Carbon-12, and this element is Carbon-13.
The figure is not marked in any way that would indicate it is a parallelogram. If we assume it is, then
... BE = DE
... 10x -3 = 8x -1 . . substitute the given expressions
... 2x = 2 . . . . . . . . add 3-8x
... x = 1 . . . . . . . . . . divide by 2
The appropriate choice is ...
... A. 1 unit
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Since the figure is not marked to indicate BE=DE, you could argue that any answer is correct.
I believe the answer is "b", sorry if i am incorrect.