1. Safety goggles must be worn at all times while working in the laboratory, even when cleaning up after an
experiment.
2. The fire blanket should be used to smothes chemicals that
have caught fire.
3. Hot plates should be turned off whenever not in use,
unless they are going to be used again in a minute or two.
4. It is occasionally permissible to taste substances in the lab
to determine their identity.
5. The teacher should be notified of all chemical spills, unless
they are very minor.

You are studying several alleles of an e. coli helicase gene. one allele, called rsr, confers resistance to rs2014, an antibiotic that works by inhibiting helicase activity. bacteria with the rss allele are sensitive to rs2014. another allele, called ts-, produces a temperature sensitive mutation of the helicase. in bacteria with the ts- allele, helicase is inactivated at 42 °c but functions normally at 37 °c. helicase functions normally at both temperatures in bacteria with the ts allele. you obtain the following data while testing four strains of e. coli at different temperatures and doses of rs2014. each number represents the percentage of maximal dna synthesis. based on this data, assign the appropriate genotype to strains a–d in the spaces provided