Question

body heat might sound like an unlikely source of power, but it has several advantages compared to oil and other traditional sources of energy: it is free, renewable, and available everywhere. furthermore, traditional energy sources will someday be depleted. so even people with access to electricity hope to exploit alternative sources — such as these three other unusual possibilities. jellyfish read paragraph 2. highlight the detail that tells you the meaning of alternative.

Explanation:

在文中，“alternative”意为“替代的、可供选择的”。通过“such as these three other unusual possibilities”（比如这三种其他不寻常的可能性）可以看出，“alternative sources”（替代能源）是与传统能源（如石油）相对的，是除传统能源之外的其他可供选择的能源。

Answer:

such as these three other unusual possibilities