Questions: Why are jatropha plants grown for biofuel over other crops? The seed contains a high oil content. The rainy climate is good for growing the plants. The plants do not take up much field space. The fruits can also be eaten.

The answer is the first one: The seed contains a high oil content.

Explanation for each option:

1. The seed contains a high oil content.
   This is correct. Jatropha plants are primarily grown for biofuel because their seeds have a high oil content, which can be converted into biodiesel. This makes them an attractive option for biofuel production.

2. The rainy climate is good for growing the plants.
   This is incorrect. Jatropha plants are known for their ability to grow in arid and semi-arid conditions, not specifically in rainy climates. They are drought-resistant and can thrive in poor soils where other crops might not survive.

3. The plants do not take up much field space.
   This is incorrect. While jatropha plants can be grown on marginal lands, the statement about not taking up much field space is not a primary reason for their cultivation for biofuel. The focus is more on their ability to grow in less fertile areas rather than the space they occupy.

4. The fruits can also be eaten.
   This is incorrect. Jatropha fruits are not typically consumed by humans as they are toxic. The primary use of jatropha is for its seeds, which are processed for oil extraction.

In summary, jatropha plants are grown for biofuel primarily because their seeds contain a high oil content suitable for biodiesel production.