Dr. digger, a paleontologist, finds a fossil that he describes in his journal. the creature was approximately 1 meter long, with its backbone fused into a large shell covering the body cavity. it had a beaklike mouth, without teeth, and all four limbs were in the form of flippers. based on anatomical similarities, to which modern animal is dr. digger’s creature most closely related?
zebra, bony fish, sea turtle, or snake

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