Questions: The amount of original solar energy moving from plants to animals that eat plants is: 10%. 5% 1%. 2%.

The answer is the first one: 10%.

Explanation for each option:

1. 10%: This is the correct answer. In ecological energy transfer, it is commonly accepted that approximately 10% of the energy from one trophic level is transferred to the next. This is known as the "10% rule" in ecology, which states that when energy is passed in an ecosystem from one trophic level to the next, only about 10% of the energy is passed on.

2. 5%: This is incorrect. While energy transfer efficiency can vary, the standard rule is 10%, not 5%.

3. 1%: This is incorrect. 1% is too low for the typical energy transfer from plants to herbivores.

4. 2%: This is incorrect. Like the 1% option, 2% is also too low compared to the standard 10% rule.

In summary, the correct answer is 10%, as it aligns with the widely accepted ecological principle regarding energy transfer between trophic levels.