In 1937, a man employed to lay water pipes was found to be the source of a severe epidemic of typhoid fever. The man, an asymptomatic carrier of Salmonella enterica serotype Typhi, the bacterium that causes typhoid, habitually urinated at his job site. In the process, he contaminated the town’s water supply with bacteria from his bladder. Over 300 cases of typhoid fever developed, and 43 people died before the man was identified as the carrier. How was this carrier identified?
a. nasal swab
b. sputum sample
c. throat swab
d. urine culture

Sydney drew a flow chart to illustrate the nitrogen cycle. which labels best complete the flow chart? x: producers undergo photosynthesis. y: nitrogen compounds are released into the air. x: nitrogen compounds are released into the air. y: producers undergo photosynthesis. x: free nitrogen is in the atmosphere. y: producers absorb nitrogen compounds through their roots. x: producers absorb nitrogen compounds through their roots. y: free nitrogen is in the atmosphere.

Getting out of bed is the first goal i tackle each day. 2several small goals are achieved by me as the day progresses. 3when i am riding the bus home or walking the dog, i think about the bigger goals i have for my life. which statement correctly describes the verb tense, aspect, and voice in this paragraph? a. sentences 1 and 2 contain present progressive verbs. sentence 3 contains both present progressive and simple present verbs. sentence 2 uses passive voice. b. sentences 1 and 2 contain simple present verbs. sentence 3 contains present progressive verbs. all three sentences use active voice. c. sentences 1 and 2 contain present progressive verbs. sentence 3 contains simple present verbs. all three sentences use active voice. d. sentences 1 and 2 contain simple present verbs. sentence 3 contains both present progressive and simple present verbs. sentence 2 uses passive voice.

Which of the following factors would not contribute to allopatric speciation? a) a population becomes geographically isolated from the parent population. b) the separated population is small, and genetic drift occurs. c) the isolated population is exposed to different selection pressures than the ancestral population. d) different mutations begin to distinguish the gene pools of the separated populations. e) gene flow between the two populations is extensive.