Science Focus 2 - Coursebook Answers - Pearson Australia Media ...

Answers to coursebook questions Chapter 415 Cholesterol.16 Electrocardiogram.17 Plastic or animal tissue (eg pig).Thinking questions18 a We excrete when we breathe out.b Water and carbon dioxide are waste products of cells.c Our kidneys are about the size of our fists.d Kidneys filter about a quarter of the blood pumped by the heart in the same time.e Urine travels down tubes called urethras to the bladder, which has a capacity ofabout 1 litre.f Drinking at least a litre of water each day decreases the risk of kidney stones.g It is possible to live normally with only one kidney.19 Fats contain about twice the energy of carbohydrates. Various answers for menu.20 A sphincter opens or closes a section of the digestive tract, while peristalsis movesmatter through it.21 a Ulcer.b Appendicitis.c Cirrhosis.22 They both consist of glucose molecules. Glycogen can be stored in muscle tissue.23 Vein—return blood to heart, artery—high pressure, capillary—fine tubes near cells.24 a ib vc ivd iiie ii and vif viInterpreting questions25 Contracts, contract, upwards, outwards, increase, decrease, flows in.26 a • Thin moist surface.• Large surface area.• Lie close to the circulatory system.b • For efficient diffusion of gases.• For maximum rate of diffusion.• To transport gases to cells.27 Calcium 1100 mg, sodium 2000 mg, protein 60 g, iron 14 mg.28 12.8 kJ (male), 9.4 kJ (female). Answers vary with age.29 a No.b Yes.c No.d No.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.