2NH3 is equivalent to N2 + H6 since the 2 at the beginning gets distributed to both atoms. Knowing this you can rewite the equation as
H2 + N2 = H6 + N2
The N2 can cancel out leaving
H2 = H6
You now have to ask ‘2 times what equals 6?’ The answer is obviously 3 at this point.
Answer: C. 3
Microtubules are filamentous intracellular structures that are responsible for various kinds of movements in all eukaryotic cells. Microtubules are involved in nucleic and cell division, organization of intracellular structure, and intracellular transport, as well as ciliary and flagellar motility.