When Did the World Population Reach 6 Billion

question 21

Multiple Choice

When did the world population reach 6 billion?

• A)Not yet: it is expected to reach 6 billion by 2010
• B)Not yet: it is expected to reach 6 billion by 2020
• C)1985
• D)1990
• E)Late 1990s

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Definitions:

Channels

Pathways or conduits through which substances such as ions or molecules can move across cell membranes or within the body or an organism.

Calcium

A chemical element essential for living organisms, particularly in cell physiology, where it plays a key role in various bodily functions including bone formation, muscle contraction, and blood clotting.

Potassium

A chemical element (K) and a key electrolyte in the body, crucial for nerve function, muscle contraction, and maintaining fluid balance.

Action Potential

A sudden, temporary reversal of the electrical charge across a cell membrane, which travels along neurons to transmit signals.