Hint: They have a cephalothorax and an abdomen, which distinguishes them from other animals. They also have six appendages: four pairs of legs and two pairs of mouthpart appendages, the first of which are known as chelicerae (hence, the subphylum Chelicerata). Pedipalps are the second set of mouthpart appendages.
Option A: The presence of metamorphosis is the characteristics of the amphibians. So, option A is incorrect.
Option B: The presence of poison is found commonly in reptiles. So, option B is incorrect.
Option C: Arachnids have eight legs in them. So, option C is incorrect.
Option D: Spiders, scorpions, ticks, mites, harvestmen, and their cousins all belong to the Arachnida class of arthropods. Arachnids, which include most spiders, have over \[75,000\] species described by scientists. Most arachnids are both carnivorous (they eat insects) and terrestrial (they live on land). Arachnids provide a valuable function by controlling insect populations. Scorpions, on the other hand, live young and are either ovoviviparous or viviparous, depending on the species. So, option d is correct.
Hence, the correct answer is option D.
Arachnids (class Arachnida) are the second most numerous groups of terrestrial arthropods (phylum Arthropoda), after the class Insects. There are over \[70,000\] different species of arachnids, including scorpions, crabs, harvestmen or daddy longlegs, ticks, and mites, as well as lesser-known whip scorpions, pseudoscorpions, and sun spiders. Arachnids belong to the Chelicerata subphylum, which includes the phylogenetically related (by evolution) ancient horseshoe crabs.
Arachnids are invertebrate species that belong to the class of arachnids. They belong to the arthropod family. They belong to the Chelicerata subphylum. Arachnids have eight legs in common. They are mostly terrestrial in nature. Spiders and scorpions are examples of these species. This characteristic distinguishes arachnids from insects. Because the insects are believed to have six wings.