You are testing a new antibiotic in the microbiology lab. After treating Salmonella cells with the antibiotic, you wanted to see how many viable cells remain. Which of the following methods will provide the most accurate count of viable cells? A. Fluorescence-activated cell sorting of unstained cells. B. Serial dilution followed by an optical density measurement. C. Counting cells directly using a hemocytometer. D. Serial dilution followed by a colony forming units calculation.

D. Serial dilution followed by a colony forming units calculation.

Explanation:

The best way to count bacterial cells such as Salmonella accurately is through serial dilution and calculation of colony forming units.

Serial dilution is made using a petri dish containing appropriate culture medium for Salmonella growth. In this petri dish, with the help of an inoculation loop, the suspension containing the Salmonella will be scratched in the middle of the petri dish. Then, the inoculation loop will be passed over the salmonella streaks and will be dragged to the other side of the plate, where the loop will be scratched halfway through this space. The inoculation loop should again pass over the new salmonella streaks and be dragged through the rest of the petri dish. Then one must wait for the bacterial colonies to grow inside the plate.

Once these colonies are grown, those that appear in isolation will be counted through a specific calculation for the count of salmonella colonies.

answer: - few nutrients

high pressure

low temperatures

explanation: 1. few nutrients:   open-ocean zone is located way far from the land, which is the main source of the essential nutrients.2. high pressure: pressure increases by 1 atmosphere for every 10 meters increase in depth.3. ample sunlight: a large fraction of the sunlight is reflected back to the atmosphere from the sea surface. 4. varying salinity: below the thermocline, the water is isolated from the atmosphere so the salinity remains stable over the year.5. low temperatures:   the temperature of open-ocean zone ranges from a low of -2°c to an average of 17°c

idk what the options are but

these is a strong electrostatic attraction between the ions hence a lot of energy is needed to overcome this attraction

this is why the boiling points are so high