biology-today_2015-03
• mammals can locate upto 4000 different odours. • The receptors for smell occur in a small (about 5 cm^2 ) patch of olfac ...
in diameter and consists of tissues present in three concentric layers : Outermost fibrous layer consists of sclera and cornea. ...
• cornea allows the light to pass into the eye. Due to its curvature, it helps in focusing a real inverted image of the objec ...
of cells. Beginning from the choroid side, it has a layer of pigmented cells, a layer of receptor cells, a layer of bipolar nerv ...
2>=24?C <0? $PSQVTMVUFVN 'PMMJDMFT $FS WJY @bY]QbicUh_bWQ^c ...
Table : Differences between rod cells and cone cells Rod cells Cone cells rod cells are far more numerous than cone cells, abou ...
: large anterior one, between iris and cornea and a small posterior region between the iris and the lens. • Both the parts of ...
• The two lacrimal canaliculi join to form a lacrimal sac. • The tears flow into the superior and inferior canaliculi, the ...
Light And dArk AdAptAtion • Light adaptation is the ability of the eye to quickly adjust when we move from the dark into the ...
• Primates and predatory animals, such as owl and cat, have binocular vision. • In some animals, such as rabbit, birds, ea ...
Table : Various eye defects and their corrective measures Eye defect Reasons Corrective measures Myopia or near sightedness In ...
huMAn EAr • The ear is the organ that detects sound. It not only acts as a receiver for sound, but plays a major role in the ...
secondary tympanic membrane. The latter is responsible for equalizing the pressure on either side of the tympanic membrane. Func ...
semicircular ducts • There are present three semicircular ducts; the anterior, the posterior and the lateral semicircular duc ...
• The cochlea contains 16,000 to 24,000 hair cells arranged in four rows. In three of the rows, the hair form V-shaped patter ...
Intext Practice Questions Name the three ossicles and state their function. Why is organ of Corti said to be the organ of heari ...
Tongue is a (a) rheoreceptor (b) teloceptor (c) nociceptor (d) gustatoreceptor. Which one of the following is the correct diffe ...
a person is wearing spectacles with concave lenses for correcting vision. While not using the glasses, the image of a distant o ...
match column-I with column-II and select the correct option. Column-I Column-II I. Incomplete digestive system a. Sponges II. c ...
Which of the following is not matched correctly? (a) Anabaena – cyanobacteria (b) Gonyaulax – Dinoflagellates (c) Thermoacidoph ...
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