In a nutrient medium that lacks histidine, a thin layer of agar containing around 10^9 Salmonella typhimurium histidine auxotroph produces around 13 colonies over a two day incubation period at 37 degrees centigrade. How do these colonies arise in the absence of histidine? The experiment is repeated in the presence of 0.4 micrograms of 2-aminoanthracene. The number of colonies the number of colonies produced over 2 days exceeds 10,000. What does this indicate about 2- anthracene? What can you surmise about its carcinogenicity?

To store strawberries in sugar syrup, lucy placed them in a jar and covered them with sugar but did not add any water. do you think syrup will be formed? justify. a. no. since water is not added, there cannot be any syrup formation. b. no. the higher concentration of sugar on the outside will cause the water from the sugar to diffuse in the strawberry cells causing them to swell without formation of any syrup. c. yes. the higher concentration of sugar on the outside will cause the water from the strawberry to diffuse out resulting in syrup formation. d. yes. the sugar will melt over time and form the syrup.