A.I. Explanation:

Option 1: "Snakes are good receptors of external information due to their VNO."

Explanation: This option accurately summarizes the main idea of the text, which emphasizes the role of the vomer nasal organ (VNO) in snakes' ability to detect and process chemical signals from their environment. The text states that snakes communicate through chemical signals and that the VNO is specialized for this purpose, making them effective receptors of external information.

Option 2: "Not only snakes possess a Jacobson's organ, as some mammals also have it."

Explanation: While it is true that other vertebrates have similar organs, the text does not focus on mammals or suggest that they possess a Jacobson's organ at the same level of efficiency as snakes. This option introduces information that is not explicitly supported by the text, making it misleading.

Option 3: "Snakes can recognize the food they eat by means of their VNO."

Explanation: This option is incorrect because the text does not specifically mention that snakes use their VNO to recognize food. Instead, it discusses their ability to detect chemical signals in general, which may include food but is not limited to it. Thus, this option presents partial information.

Option 4: "Although the brains of snakes are extremely small in proportion to their bodies, they survive thanks to their VNO."

Explanation: This option introduces a comparison about the size of snakes' brains that is not mentioned in the text. The text focuses on the VNO's role in communication and chemical detection, without discussing brain size or survival in relation to it. Therefore, this option contains contradictory information.