Cells Grown in a Petri Dish Tend to Divide Until

question 35

Multiple Choice

Cells grown in a petri dish tend to divide until they form a thin layer covering the bottom of the dish. If cells are removed from the middle of the dish, the cells bordering the open space will begin dividing until they have filled the empty space. What does this experiment show?

• A) When cells come into contact with other cells, they stop growing.
• B) The controls on cell growth and division can be turned on and off.
• C) Cell division can be regulated by factors outside of the cell.
• D) Cells continue to grow as long as there is adequate space.
• E) All answers are valid and correct.

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Definitions:

Socially Active

Engaging in and contributing to community or social group activities, showing involvement with others in public contexts.

Operant Conditioning

A learning process by which the strength of a behavior is modified by reinforcement or punishment.

Token Economy

A form of behavior modification that uses tokens or symbols as reinforcement for desired behaviors, which can be exchanged for rewards.

Classical Conditioning

A learning process that occurs through associations between an environmental stimulus and a naturally occurring stimulus, famously demonstrated by Pavlov’s dogs.