question_answer 47)

    Fill up the blank spaces appropriately

Phylum/Class	Excretory Organ	Circulatory Organ	Respiratory Organ
Arthropoda     Amphibia	Nephridia Metanephridia	Closed Open Closed	Lung/Gills/Tracheal System Skin/Para podia   Lung

Answer:

                  Excretion involves the elimination of metabolic waste products from the animal body. Different organs are involved in the process of excretion in different animals. (a) In Arthropods, the Malpighian tubules remove excretory products from haemolymph. (b) In Annelids, the excretory organ occurs as segmentally arranged coiled tubules called nephridia (c) In Molluscas, excretion occurs by paired structures called organ of Bojanus also called metanephridia. (d) In Amphibians mesonephric kidneys are associated with excretion. Blood circulation involves the circulation, of blood and lymph along with oxygen, carbondioxide, hormones, blood cells, etc, within the body system for the nourishment of cells , fighting diseases, and for stabilizing body temperature and pH.

Open Circulation	Closed Circulation
In this, blood is pumped out of the heart into sinuses which directly open into cells and tissues, e.g., phylum-Arthropoda, and Mollusca.	In this system, blood is circulated through a series of complexly arranged vessels and capillaries e.g., phylum-Annelida and Class-Amphibia.

Respiratory organs are involved in the exchange of gases from the atmosphere. Different respiratory organs are as follows (a) Lungs/gills/tracheal system in arthropoda and molluscs. (b) Skin in annelids.                                                         (c) Lungs and skin in amphibians.