Which of the following statements about the import of protein to the nucleus is correct? choose all that apply.

an nls can be a monopartite or bipartite signal which includes a significant number of basic amino acids.
gtp is required for an importin to bind to an nls of a protein destined to be localized to the nucleus.
ribosomal proteins must display an nls to be localized to the nucleus, and an nes to be localized to the nucleolus.
the recycling of importins back to their original conformation requires gtp hydrolysis in the cytoplasm.

The correct statements are:

•An NLS can be a monopartite or bipartite signal which includes a significant number of basic amino acids.

• The recycling of importins back to their original conformation requires GTP hydrolysis in the cytoplasm.

The other answers are incorrect because GTP is not required for an importin to bind to an NLS but for the release of importin and an NES or nuclear export signal  is the sequence  in a protein for export from the cell nucleus to the cytoplasm, not to the nucleolus.

answer: b: experiments that showed that all cells are similar in how they metabolize and in their composition

explanation:

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.