Phylum Arthropoda
- Prawns and crabs belong to the phylum Arthropoda.
- The phylum Arthropoda is the largest phylum in the animal kingdom, comprising a diverse group of organisms.
- Arthropods are characterized by their segmented bodies, jointed appendages, and exoskeleton made of chitin.
- They exhibit a wide range of adaptations that have allowed them to colonize almost every habitat on Earth, including terrestrial, freshwater, and marine environments.

Characteristics of Arthropods
- The arthropod body is divided into distinct segments, with each segment having a pair of jointed appendages.
- The exoskeleton of arthropods provides support and protection and serves as a site for muscle attachment.
- Arthropods have a well-developed nervous system, with a brain and a ventral nerve cord.
- They possess a wide range of sensory structures, including compound eyes, antennae, and various types of sensory hairs.
- Arthropods exhibit a high degree of cephalization, with a concentration of sensory organs and nerve ganglia in the head region.

Subphylum Crustacea
- Prawns and crabs belong to the subphylum Crustacea within the phylum Arthropoda.
- Crustaceans are primarily aquatic organisms, inhabiting both freshwater and marine environments.
- They have two pairs of antennae, a pair of mandibles, and two pairs of maxillae.
- Most crustaceans have two body regions: the cephalothorax and the abdomen.
- The cephalothorax bears the head and thorax, while the abdomen is composed of multiple segments.

Importance of Arthropods
- Arthropods play significant ecological roles, serving as pollinators, decomposers, and predators.
- They are an important part of the food chain, serving as a food source for many other organisms.
- Arthropods are also of economic importance, both as a food source for humans and as pests that can damage crops and transmit diseases.
- They have been extensively studied and used as model organisms in scientific research.

In conclusion, prawns and crabs belong to the phylum Arthropoda within the animal kingdom. Arthropods are characterized by their segmented bodies, jointed appendages, and exoskeleton. Prawns and crabs specifically belong to the subphylum Crustacea, which includes a diverse group of aquatic organisms. Arthropods play important ecological roles and have economic significance.