How many pairs of legs do spiders have?

Spiders are classified as arachnids, and one of the defining characteristics of this class is that they have eight legs, which is equivalent to four pairs of legs. Each pair of legs allows for various functions such as locomotion, web-building, and prey manipulation. The design of having four pairs provides stability and agility, which are crucial for their predatory lifestyle. This anatomical feature distinguishes spiders from insects, which typically have three pairs of legs. The option indicating six pairs of legs or any others do not align with the biological structure of spiders, as they absolutely do not possess more than eight legs in total. Thus, the understanding of spider anatomy reveals that four pairs of legs is indeed the correct answer.