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Question 19N.3.SL.TZ0.c

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Date November 2019 Marks available [Maximum mark: 3] Reference code 19N.3.SL.TZ0.c
Level SL Paper 3 Time zone TZ0
Command term Explain Question number c Adapted from N/A
c.
[Maximum mark: 3]
19N.3.SL.TZ0.c

The MRI brain scans show the cerebral hemispheres of two people of the same age, one of whom is suffering from multiple sclerosis and has lost motor functions.

[Source: © Frontiers in Bioscience. Role of MRI in Multiple Sclerosis II: Brain and Spinal
Cord Atrophy, Robert Zivadinov and Rohit Bakshi, 9, 647–664, January 1, 2004]

The folding of the cerebral hemispheres is extensive and varies between different mammals. Explain briefly the importance of folding of the cerebral hemispheres in humans.

[3]

Markscheme

a. the cerebral hemispheres are responsible for higher order functions ✔

b. the folding permits an increased surface area without increasing the cranium size
OR
permits high surface area to volume ratio ✔

c. increased surface/volume permits more synapses ✔

d. humans have a highly developed/highly folded cerebral cortex ✔

e. folding decreases distances therefore faster communication ✔

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