Final answer:
The answer reliant on an illustration is the one asking about the spider's appearance, which requires visual detail that text alone cannot provide.
Step-by-step explanation:
The question that can be answered only if an illustration accompanies the text is: What does the spider look like? This question relies on visual information to provide a detailed and accurate description of the spider's appearance. Without an illustration, one might not be able to fully convey the shape, size, color, or distinctive markings of the spider.