"Two bacterial strains were obtained: Hfr: his(+) leu(+) bio(-) ton(S) Str(S) and F(-): his(-) leu(-) bio(+) ton(R) Str(R) . After an uninterrupted conjugation, you want to select ALL the F(-) recombinants that are leu(+). Which of the following media would you use for this selection?a. Complete medium containing streptomycinb. Minimal medium containing streptomycinc. Minimal medium containing leucine and streptomycind. Minimal medium containing sodium azide and leucinee. Minimal medium containing alanine, leucine, and streptomycinf. Minimal medium containing biotin, histidine, and streptomycing. Minimal medium containing alanine. h. Minimal medium containing alanine, biotin, and sodium azide."

What does the hardy-weinberg principle relate to? a. chances of survival of an organism b. frequency of alleles in a population c. natural selection in a species d. causes of evolution among organisms

Pentane with molecular formula c5h12, exists in three isomeric forms. one shows linear carbon chains, another has one -ch3 groups present on the third carbon atom, and the third has two -ch3 groups present on the second carbon atom. what types of isomers are these? a. geometric isomers b. structural isomers c. halotropic isomers

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.