Zoology - 2 (B.Sc. Agriculture)

 Birds are megalecithal.

The life history of insects usually exhibit metamorphosis.

Widal test is a confirmatory test for typhoid.

Arthropods are characterized by a chitinous exoskeleton, a haemocoel (body cavity filled with hemolymph), and gills (or gill-derived respiratory structures like book lungs or tracheal systems). This combination of features is unique to arthropods among the options given.

 Thyroxin is synthesized from iodine.Thyroxine is the main hormone secreted into the bloodstream by the thyroid gland. It is the inactive form and most of it is converted to an active form called triiodothyronine by organs such as the liver and kidneys.

Typhoid and cholera are caused by contaminated food and water.

Sand fly  spreads Kala -azar.

Sericulture is the specialized term for the rearing of silkworms for silk production. Other options refer to different agricultural practices: apiculture (beekeeping), pisciculture (fish farming), and floriculture (flower cultivation).

Three pairs of legs are attached to thorax region of a cockroach.

During anaphase, sister chromatids separate from each other and move towards the poles.

The receptors found in the muscles, tendons and joints are propriorecpetors. These are stretch recpetors. They supply information about the so called kinesthetic sense of equilibrium and orientation. They act like pressure gauges and are responsible for maintenance of body posture. 

Hirudin is a potent anticoagulant protein produced in the salivary glands of leeches (Hirudo medicinalis). It prevents blood clotting by inhibiting thrombin, allowing leeches to feed on blood without it coagulating. Hirudin has medical applications in treating blood clots.

 The term systematics was coined by Linnaeus.