Nano technology problem. Please answer both and will give good rating!

a. 7. Which characterization method provides information on the morphology of carbon nanotubes and other nanomaterials? Raman spectroscopy b. Thermogravimetric analysis c. Electron Microscopy d. X-ray diffraction 8. Which characteristic of CNTs affects most their toxicity? a. Length b. Diameter c. Catalytic metal particles d. Other carbon impurities