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

Answers to coursebook questions Chapter 4Unit 4.5 Respiratory systemsCheckpoint1StructuresTracheaEpiglottisNoseCiliaAlveolusFunctionsCarries air to and from the lungs.Prevents food from entering the trachea.To filter, warm and humidify air.To remove foreign particles from the lungs.The site of gas exchange.2 a Larynx and epiglottis.b Coughing occurs.3 Alveoli.4 a In red blood cells.b To carry oxygen from the lungs to body cells.5 Gases cannot diffuse efficiently to all body cells in the required amounts.6StructuresSkin and lungs/bloodstreamGills/bloodstreamMoist body surface/bloodstreamLungs/bloodstreamBody surface/no circulatory systemAir-filled tubes/no bloodstreamOrganismsFrogFishEarthwormLizardSingle-celled amoebaInsectThink7 a Contracts.b Enlarges.c Raised.d Contract.e Decreases.8 Allows maximum rate of gas diffusion.9 High surface area, a thin, moist surface and a means of transporting gases to andfrom cells.10 a About the same.b Less.© 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.