How could nanotechnology best be used to improve the treatment of cancer with chemotherapy? A. A nanometer-size carrier could be designed to bring the chemotherapy drugs only to cancer cells.

B. A nano carbon wire could be designed that would aid in the manufacture of chemotherapy drugs.

C. A quantum dot could be used to watch where the chemotherapy drugs go in the body.

D. Biomaterials could be made that would allow for cell growth within the cancer cells so that they are easier to find.

Uranium has two naturally occurring isotopes. 238u has a natural abundance of 99.3% and 235u has an abundance of 0.7%. it is the rarer 235u that is needed for nuclear reactors. the isotopes are separated by forming uranium hexafluoride uf6, which is a gas, then allowing it to diffuse through a series of porous membranes. 235uf6 has a slightly larger rms speed than 238uf6 and diffuses slightly faster. many repetitions of this procedure gradually separate the two isotopes. what is the ratio of the rms speed of 235uf6 to that of 238uf6? express your answer to five significant figures.