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The human hind brain comprises three parts, one of which is
spinal cord
corpus callosum
Cerebellum
hypothalamus
C.
Cerebellum
The hindbrain generally has its anterior roof enlarged to form a pair of cerebellar hemispheres. Its floor is thickened to for the pons anteriorly and the medulla oblongata posteriorly.
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Which part of the human ear plays no role in hearing as such but is otherwise very much required?
Eustachian tube
Organ of corti
Vestibular apparatus
Ear ossicles
A.
Eustachian tube
The inner ear contains a complex system called vestibular apparatus, located above the cochlea. It has no role in hearing but is influenced by gravity and movements. Its specific receptors called crista and macula are responsible for maintenance of balance of the body and posture.
The most abundant prokaryotes helpful to humans in making curd from milk and in production of antibiotics are the ones categorised as
Cyanobacteria
Archaebactera
Chemosynthetic autotrophs
Heterotrophic bacteria
D.
Heterotrophic bacteria
Heterotrophic bacteria are most abundant in nature. Many of them have a significant impact on human affairs. These are helpful in making curd from milk (e.g., Lactobacillus sp.), production of antibiotics (e.g., Streptomyces sp.) and fixing nitrogen in legume roots (e.g, Rhizobium spe).
Companion cells are closely associated with
sieve elements
vessel elements
trichomes
guard cells
A.
sieve elements
Companion cells are characteristic elements of phloem tissue associated with the sieve tubes(sieve elements) in the angiosperms. The siever tubes and companion cells are related ontogenically as they develop from the same mother cell. The companion cells and sieve tubes maintain close cytoplasmic connections through plasmodesmata.
Pheretima and its close relatives derive nourishment from
sugarcane roots
decaying fallen leaves and soil organic matter
soil insects
small pieces of fresh fallen leaves of maize
B.
decaying fallen leaves and soil organic matter
Food of earthworm (Pheretima sp.) consists of organic matter, fallen decaying leaves, algae, etc., present in the soil. Food is swallowed along with soil by sucking action.
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