Why lobster belongs to the arthropods group?

1. Segmented Body: Lobsters have a segmented body, a feature shared by all arthropods. Their body is divided into distinct sections or segments, such as the head, thorax, and abdomen, with each segment performing specific functions.

2. Jointed Appendages: Arthropods are known for their jointed appendages, and lobsters are no exception. They have multiple pairs of jointed legs that allow for efficient movement and manipulation of their environment.

3. Exoskeleton: Lobsters, like other arthropods, have an external skeleton or exoskeleton made of a tough material called chitin. The exoskeleton provides protection, support, and muscle attachment points for locomotion.

4. Open Circulatory System: Lobsters have an open circulatory system, a characteristic of many arthropods. Their circulatory system involves a series of vessels and sinuses, where the blood flows freely and directly bathes the tissues and organs.

5. Compound Eyes: Lobsters have compound eyes, a type of specialized visual organ found in various arthropods. Compound eyes consist of numerous individual lenses, known as ommatidia, that work together to provide a wide field of vision and the ability to detect movement.

6. Malpighian Tubules: Arthropods, including lobsters, possess Malpighian tubules. These are excretory structures that help regulate the body's fluid balance and remove metabolic waste products from the body.

Therefore, based on these characteristics, such as segmented body, jointed appendages, exoskeleton, open circulatory system, compound eyes, and Malpighian tubules, lobsters are rightfully classified as members of the phylum Arthropoda.