What Evidence Would Suggest That the Fluid in the Nucleus

Multiple Choice

What evidence would suggest that the fluid in the nucleus is different from the cytoplasm?

A) There is no pH difference between the two fluids.
B) Nucleoplasm flows freely back and forth between the nucleus and the cytoplasm.
C) Nuclear pores only permit passage of certain molecules into and out of the nucleus.
D) Light microscopy reveals no differences between the fluid within the nucleus and the fluid outside of the nucleus.