What are two important differences in the structures of dna and rna? the sugar of rna is ribose, rather than dna's deoxyribose. the base uracil substitutes for dna's thymine. the sugar of rna is deoxyribose, rather than dna's ribose. the base thymine substitutes for dna's uracil. rna always has a single strand, while dna always has a double strand. dna always has a single strand, while rna always has a double strand.

Below, the levels of organization in a multicellular organism are shown from least to most complex. which level of organization can be described as several different types of tissues working together to perform a common task?

What is the farthest destination to date for a human spaceflight mission?

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.