Spiracles are openings of the insect tracheal system. They allow air to enter and leave the tracheae and can help regulate water loss. This MCQ belongs to the Insecta topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Correct Answer: B. economic value as food and pearls
Explanation:
Molluscs have economic importance as food sources and in pearl production. Some species are also intermediate hosts of parasites or pests, so their impact can be both beneficial and harmful. This MCQ belongs to the Mollusca topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Septa are internal walls between segments in many annelids. They divide the coelom and help localize muscular action during movement. This MCQ belongs to the Annelida topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Compound eyes consist of many ommatidia and are common in arthropods, especially insects and crustaceans. They are useful for detecting movement and wide visual fields. This MCQ belongs to the Arthropoda topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Arthropods show remarkable adaptive diversification due to segmentation, tagmatization, jointed appendages, exoskeleton, and varied developmental patterns. These traits helped them become the most diverse animal phylum. This MCQ belongs to the Arthropoda topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Molluscs commonly possess nephridia or metanephridia for excretion. These organs help remove nitrogenous wastes and regulate internal fluids. This MCQ belongs to the Mollusca topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Earthworms exchange gases through their moist body surface, a process called cutaneous respiration. Dry skin reduces diffusion and can be fatal. This MCQ belongs to the Annelida topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Malpighian tubules are excretory organs of insects and many terrestrial arthropods. They help remove wastes while conserving water, often producing uric acid. This MCQ belongs to the Arthropoda topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
The water vascular system is a defining echinoderm feature. It operates tube feet for locomotion, feeding, attachment, and gas exchange in many species. This MCQ belongs to the Echinodermata topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Bivalves generally lack a radula because they feed by filtering suspended particles with their gills. This contrasts with gastropods, where the radula is commonly used for scraping. This MCQ belongs to the Bivalvia topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
In earthworms, the crop stores food and the gizzard grinds it with ingested particles. This supports processing of soil and organic matter. This MCQ belongs to the Annelida topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Green glands, or antennal glands, are excretory organs of many crustaceans. They help regulate salts and remove wastes in aquatic environments. This MCQ belongs to the Crustacea topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.