DNA helicases synthesize short DNA molecules important for

A. the function of DNA polymerase.
B. seal gaps between DNA fragments.
C. break hydrogen bonds between complementary nucleotides.
D. assist in recognition of promoters during transcription.
E. proofread DNA molecules.

What are the doorways into and out of cells, attached to the membrane, and built in the rough er.

Juan and carol were studying invertebrates in biology. they knew that segmented or earth worms preferred a dark, moist habitat. during this lab, they would be investigating the responses of organisms called planaria or dugesia tigrina. these were simple flatworms that still had a one-way digestive system and a very simple nervous system. juan and carol placed the planaria in a petri dish containing cool, distilled water that was partially covered with black paper. they shined a light on the dish. next, they removed the paper and placed a small amount of chicken liver at one end of the dish. they added a few large salt crystals to the water. finally, they added drops of hot water to the cool water in the petri dish. their results can be seen in the data table. according to their experiment, all but one conclusion is valid.

Nucleic acids offer variability because they contain alternate forms of genes called .