C.

Test tube containing heparin

Clotting of collected blood can be prevented by ­

1) coating test tubes with silicon (which produce non wettable surface similar in its smoothness to endothelial lining of blood vessels).

2) adding chelating agents (includes trisodium citrate, sodium oxalate and sodium EDTA) which remove calcium which is important for blood coagulation, and prevent blood clotting.

3) adding heparin, most powerful anticoagulant which acts indirectly by activating plasma antithrombin III. Heparin is effective both in vivo and in vitro. Whereas the option a, b and d are effective in vitro. Heparinized blood is not suitable for blood counts (as it alters the shape of RBC's and WBC's which affects blood testing), Fragility testing and complement fixation tests.

C.

may suffer vitamin K deficiency and prolonged bleeding

Dicumarol is an anticoagulant found in spoilts sweet clover causes hemorrhage and other symptoms of bleeding disorder by disrupting vitamin K metabolism and preventing the activation of prothrombin and certain other clotting factors by the liver.

B.

By propagating through vegetative multiplication

The propagation through vegetative multiplication is used to maintain the genetic traits of a given plant. It gives rise to genetically uniform population or clone. In case of plants propagated through seeds, variations creep in due to chance segregation of genes during meiosis and their chance combination during fertilization.

B.

growth regulators synthesised by plants and influencing physiological process

Growth regulators are organic substances, other than nutrients, which in low concentration regulate growth, differentiation and development by promoting or inhibiting the same. Phytohormones are growth regulators produced naturally in plants and translocated to another region for regulating one or more physiological reactions when present in low concentration. Phytohormone can have a promoting or inhibiting effect on a process

D.

closing of eyes when strong light is flashed across them.

Simple or unconditional reflexes are present in an individual right from birth. They are specific, predictable, purposeful and have survival value, e.g. breast feeding and swallowing in newly born babies and blinking of eyes are examples of unconditioned reflexes.

(a), (b) and (c) are the examples of conditional reflexes and are not present at birth but develop later in life through learning habit.