During an experiment, the same type of bacteria is grown in two petri dishes. Petri dish A has a diameter of 51 mm and has approximately 40,000 bacteria after 1 hour. Petri dish B has a diameter of 75 mm and has approximately 72,000 bacteria after 1 hour. Determine and state which petri dish has the greater population density of bacteria at the end of the first hour.

Petri Dish A with a Population density of 19.6 bacteria/mm² has a higher population density at the end of the first hour.

Explanation:

Population density = number of bacteria/area of dish

For Petri dish A

Area of dish = πd²/4 = (22/7) * 51² / 4 = 2043.64 mm²

Population density = 40000 bacteria / 2043.64 mm² = 19.6 bacteria/mm²

For Petri dish B

Area of dish = πd²/4 = (22/7) * 75² / 4 = 4419.64 mm²

Population density = 72000 bacteria / 4419.64 mm = 16.29 bacteria/mm²

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