Question

historically, what contributed to the zero population growth of humans? environmental resistance and biotic potential abundant food supplies everywhere no clean water sources

Explanation:

To determine what contributed to zero population growth historically, we analyze each option:

• "Environmental resistance and biotic potential": Environmental resistance (factors limiting population growth like disease, resource scarcity) and biotic potential (maximum reproductive capacity) interact. When environmental resistance balances biotic potential, population growth can be zero.
• "Abundant food supplies everywhere" would likely increase population growth, not lead to zero growth.
• "No clean water sources" is a specific environmental resistance factor, but alone it doesn't fully explain zero population growth as other factors (like food, disease) also matter, and the option "environmental resistance and biotic potential" is a more comprehensive explanation of the balance needed for zero growth.

Answer:

A. environmental resistance and biotic potential