As we look to 2050, when we will need to feed two billion more people, the question of which diet is best has taken on new urgency. The food we choose to eat in the coming decades will have dramatic ramifications for the planet. Simply put, a diet that revolves around meat and dairy, a way of eating that is on the rise throughout the developing world, will take a greater toll on the world’s resources than one that revolves around unrefined grains, nuts, fruits and vegetables.

What is the critical message conveyed by the above passage ?

The correct option is: "Our increasing demand for foods sourced from animals puts a greater burden on our natural resources."

Step-by-Step Explanation:

1. Identify the core subject of the passage: The passage discusses the urgency of choosing the right diet to feed an additional two billion people by 2050 and the environmental impact of these dietary choices.

2. Analyze the comparison made in the passage: The author directly compares two dietary paths:
- A diet revolving around meat and dairy (foods sourced from animals).
- A diet revolving around unrefined grains, nuts, fruits, and vegetables (plant-based foods).

3. Examine the consequences stated: The passage explicitly states that the meat and dairy-centric diet, which is rising in demand throughout the developing world, "will take a greater toll on the world’s resources" compared to the plant-based diet.

4. Match the passage's conclusion with the options: The statement that animal-based diets take a "greater toll on the world's resources" directly corresponds to the idea that animal-sourced foods place a "greater burden on our natural resources." Therefore, this option accurately captures the critical message conveyed by the passage.