Why Do Streptococcus Pneumoniae Colonies on SBA Sometimes Appear Like

question 31

Multiple Choice

Why do Streptococcus pneumoniae colonies on SBA sometimes appear like a coin-raised edges and a depressed center?

• A) The older growth at the center is smaller due to lack of nutrients.
• B) The newer growths on the outside of the colony undergo the Quellung reaction.
• C) The older growth at the center is killed due to autolysis.
• D) The newer growth has a thicker capsule, therefore it appears raised.

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Definitions:

Variable Expense

Expenses that fluctuate with changes in production volume or level of activity, similar to variable costs.

Operating Leverage

A measure of how revenue growth translates into growth in operating income.

Percentage Change

A mathematical calculation that shows how much a quantity has increased or decreased as a percentage of its previous value.

Net Operating Income

The profit generated from normal business operations, excluding expenses from interest and taxes.