IGCSE Biology Paper-4: Specimen Questions with Answers 196 - 197 of 279

Passage

A diagram of a mammalian heart and associated blood vessels is shown in Fig.

Structure of Heart

Question 196 (2 of 2 Based on Passage)

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Arrange the alphabets from Fig. to show the pathway taken by deoxygenated blood and oxygenated blood from the heart towards the lungs.

Explanation

Question 197

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Shows the skulls of a tiger and a rabbit.

Tiger and Rabbit Teeth

State two ways in which the teeth of a tiger differ from the teeth of a rabbit, using evidence from Fig.

Explanation

Rabbits have four incisors, two on the top, and two on the bottom. Right behind the top incisor teeth are two small peg-like teeth called auxiliary incisors or “peg teeth.” In addition, rabbits have cheek teeth that they use to grind their food. These are the 6 upper premolars, the 4 lower premolars, 6 upper molars and 6 lower molars. Canines are absent in rabbit.

A Rabbit՚S Skull

Tigers have 30 teeth. The canine teeth of the tiger are larger than those of any of the other wild cats, reaching lengths of almost 10 centimeters. These teeth are very sensitive, filled with neural receptors and enabling the tiger to kill its prey quickly and effectively. This reduces the suffering of the prey as well as the amount of energy that the tiger needs to invest in each kill. Then, the back teeth (carnassials) slice the meat off the carcass of the catch.

The Canine Teeth of the Tiger

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