When Counting Colonies on an Agar Plate

question 30

Multiple Choice

When counting colonies on an agar plate

• A) it is assumed that each colony arose from division of one or a few cells.
• B) only viable colonies are counted.
• C) the medium must be suitable for colony growth.
• D) All of these answer choices are true.

---

Definitions:

Ozone

A molecule composed of three oxygen atoms, found in the Earth's stratosphere, where it forms a layer that protects life by blocking most of the sun's harmful ultraviolet radiation.

Stratosphere

The second major layer of Earth's atmosphere, just above the troposphere and below the mesosphere, known for containing the ozone layer.

Antarctica

The Earth's southernmost continent, containing the geographic South Pole, known for its extensive ice sheets and cold climate.

Ozone Depletion

The reduction of the ozone layer in the Earth's stratosphere caused by the release of certain chemical compounds, leading to increased ultraviolet radiation reaching the Earth's surface.