A Mass Extinction,in Which the Dinosaurs Disappeared from Earth,occurred Approximately

question 31

Multiple Choice

A mass extinction,in which the dinosaurs disappeared from Earth,occurred approximately ____ years ago.

• A)6500
• B)65,000
• C)650,000
• D)65,000,000
• E)650,000,000

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Definitions:

Breathing

The process of inhaling and exhaling air to facilitate gas exchange within the body.

Tissue Capillaries

The smallest blood vessels in the body, located within the tissues, where gas and nutrient exchange occur.

Oxygen

A chemical element with symbol O and atomic number 8, essential for most life forms on Earth as a critical component of the air we breathe.

Carbon Dioxide

A colorless, odorless gas produced by burning carbon and organic compounds and by respiration. It is naturally present in air and is absorbed by plants in photosynthesis.