Question

How many legs does a spider have?

Answer 1

Hint: Spider belongs to the class arachnids of the phylum arthropod. These animals have jointed appendages. The body bears several segments.

Complete Answer: -
Spider is an invertebrate which belongs to the phylum Arthropoda. These organisms have chitinous exoskeleton and jointed appendages. The legs or limbs of the spider are used for locomotion and also to catch the prey. The limbs of spiders have seven segments in their legs. The spider belongs to class arachnids which have 4 pairs of jointed legs.
The legs of the spider consist of segments called coxa, trochanter, tibia, femur, patella, metatarsus and tarsus. The end of the tarsus has claws which differ in size and number. The spider legs function in a unique way which helps them in locomotion. The body of the spider contains hemolymph which is similar to the blood in case of vertebrates. When the spider has to extend its legs, the hemolymph is pumped from the body of the spider which fills the lower side of the femur-patella and tibia-metatarsus joints. This exerts a pressure on the bellow-like structure which helps in extending the leg.
The spiders have a sensitive sense organ called setae on their legs. This set performs the function similar to that of antennae like gathering sounds, vibrations, picking up smell and also air currents. The spiders also use their legs at the time of mating.
Spiders have 8 legs.

Note:
Another important class in the arthropods is insects. They are the largest class in this phylum. These invertebrates also bear appendages which are six in number unlike arachnids. They use their appendages for walking, flying and also swimming.