NEET Biology Solved Question Paper 2008

In radial symmetry, body is divided into similar halves by more than two planes passing through one main axis. Eg. Cnidarians or coelenterates such as Hydra, sea anemone, Aurelia, Obelia) are radially symmetrical animals with cell-tissue grade of body organization.

Boring sponges, such as Cliona, attach themselves to shells of oysters, clams, barnacles etc, boring them so full of holes that their contained animals are destroyed and in time, the shells are entirely broken up. Lime of these shells gets dissolved into sea water to be used over again by other animals. Sometimes, these boring sponges may prove great nuisance to oyster beds.

Antidiuretic hormone (ADH) controls the tubular permeability and concentration of sodium in the extracellular fluid. It associates with the renal pressure system and then regulates the fluid volume of body through the agency of hypothalamic osmoreceptors.

The eustachian tube is a canal that connects the middle ear to the nasopharynx, which consists of the upper throat and the back of the nasal cavity. The function of eustachian tube is to equalize air pressure on both sides (external and middle ear) of tympanic membrane. Thus, it connects middle ear with external ear.

Cholecystokinin (CCK) stimulates the gall bladder to rhythmic contraction and this results in an increase in the rate of bile transport into duodenum.

Ascorbic acid or Vitamin- C has virucidal property and in its excess amount is excreted in urine because it is water soluble.

During pachytene stage, crossing over takes place. It is exchange of equal segments of non-sister chromatids belonging to homologous chromosomes. The chromosome pair (i.e. bivalent) consists of four chromatids and thus crossing over takes place at four stranded stage.

Spleen acts as a blood bank. The sinuses of spleen acts as reservoir of blood.

Vital Capacity is defined as the sum of inspiratory reserve volume, tidal volume and expiratory reserve volume, that is, 3100 + 500 + 1200 = 4800. Therefore, 4800 mL is the vital capacity in humans.

Progeny with blood group B will be produced when man is heterozygous, that is, I^AI^O.