You Have Some Old Plastic Petri Dishes That You Would

question 78

Multiple Choice

You have some old plastic Petri dishes that you would like to use for pouring bacteriological agar plates.The only method of physical sterilization is ultraviolet radiation sterilization with your UV light (you cannot use the autoclave because it will disfigure and melt the plastic) .After sterilizing the plates, pouring the sterilized agar medium, and then leaving the plates out at room temperature for a day or two to let them solidify and dry, you find contaminating bacterial colonies growing on the agar.Predict what has happened in this situation.

• A)The room temperature enhanced the growth of normal biota of the agar.
• B)Air got into the poured agar plates, contaminating them.
• C)The lids of the Petri dishes were inadvertently left on while being sterilized.
• D)The agar had bacteria in it, even after sterilization in the autoclave.

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Definitions:

Aggregate Demand Curve

The aggregate demand curve represents the total demand for goods and services in an economy at different price levels, generally showing an inverse relationship between price and output demanded.

Price Level

An index that measures the average changes in prices received by domestic producers for their output, affecting the purchasing power of money.

Cost-Push Inflation

An inflationary trend that results from an increase in the cost of production, leading to a decrease in supply and an increase in prices.

Demand-Pull Inflation

Inflation that occurs when aggregate demand in an economy outpaces aggregate supply, leading to an increase in prices.