Question

Excretory organ of crabs is
A) Nephridium
B) Flame cell
C) Coxal gland
D) Malpighian tube

Answer 1

Hint:The crabs belong to crustacean order and they are the members of the arthropods phylum. It is the most diverse phylum of the Earth. They have different features that distinguish them from the similar organisms related to crabs.

Complete answer:
To answer this question, we should know about the physical characteristics of crabs. A crab has a thorax attached with the small tail and thick skeleton with a pair of claws. In place of lungs they consist of gills. They have a short and flat circular body. They are related to shrimp, crayfish, lobsters; they consist of two legs and two eyes and live in the shell that they change every time so they get fit with the growing body. They are mostly aquatic and are arthropods as they have two pairs of appendages in the front part of the mouth that work as jaws. The abdomens of the crabs are mostly small that they carry their eggs. They have teeth inside the stomach; the exoskeleton structure of the stomach grinds the food.
Now, the excretory organ of crabs is called colex gland. They consist of green glands that are attached to the second antennae that they use for excretion. They have two chambered stomachs with a special grinding mill. They remove the waste products through the telson opening; it is the last segment on their body.
The nephridium is the excretory organ found in phylum Annelida, the flame cells is the excretory part of phylum Platyhelminthes, and the Malpighian tube is the excretory organ of the phylum Arthropoda.

Hence, the correct answer is option ‘C’ Colax gland.

Note:The other arthropods like, myriapods, arachnids, and the insects such as, mites and spiders have Malpighian tubules as the excretory organs not the Colax gland. It is the projections of the digestive tract that help in water conservation.