Acknowledgements

CAMBRIDGE UNIVERSITY PRESS

University Printing House, Cambridge CB2 8BS, United Kingdom

One Liberty Plaza, 20th Floor, New York, NY 10006, USA

477 Williamstown Road, Port Melbourne, VIC 3207, Australia

314-321, 3rd Floor, Plot 3, Splendor Forum, Jasola District Centre, New Delhi - 110025, India

79 Anson Road, #06-04/06, Singapore 079906

José Abascal, 56 -1º, 28003 Madrid, Spain

Cambridge University Press is part of the University of Cambridge.
It furthers the University's mission by disseminating knowledge in the pursuit of education, learning and research at the highest international levels of excellence.

www.cambridge.org

© Cambridge University Press 2020

This publication is in copyright. Subject to statutory exception and to the provisions of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press.

First published 2020

ISBN 978-84-9036-315-7

Additional resources for this publication at www.cambridge.es/naturalscience

Cambridge University Press has no responsibility for the persistence or accuracy of URLs for external or third-party internet websites referred to in this publication, and does not guarantee that any content on such websites is, or will remain, accurate or appropriate. Information regarding prices, travel timetables, and other factual information given in this work is correct at the time of first printing but Cambridge University Press does not guarantee the accuracy of such information thereafter.

The authors and publishers acknowledge the following sources of copyright material and are grateful for the permissions granted. While every effort has been made, it has not always been possible to identify the sources of all the material used, or to trace all copyright holders. If any omissions are brought to our notice, we will be happy to include the appropriate acknowledgements on reprinting & in the next update to the digital edition, as applicable.

Key: U = Unit, Ex = Exercise, EOY = End of Year

Standard

Photo acknowledgements

All the photographs are sourced from Getty Images.

U1 Ex 1 (photo a), U1 Ex 2 (photo g), U1 Ex 6 (photo c): Yulia-Images/iStock/Getty Images Plus; U1 Ex 1 (photo b), U6 Ex 1 (nice): Hero Images; U1 Ex 1 (photo c), EOY Ex 1 (photo a): Sebastian Kaulitzki/Science Photo Library; U1 Ex 1 (photo d), U2 Ex 6 (photo c): KidStock/Blend Images; U1 Ex 1 (photo e), EOY Ex 1 (photo c): Monsterstock1/iStock/Getty Images Plus; U1 Ex 1 (photo f), U6 Ex 2 (photo a), U6 Ex 6 (photo d), U1–2 Ex 1 (photo c): Westend61; U1 Ex 1 (photo g), U1 Ex 2 (photo d), U1–2 Ex 1 (photo d), EOY Ex 1 (photo b): Thomas Barwick/DigitalVision; U1 Ex 2 (photo a): Peter Augustin/Stone; U1 Ex 2 (photo b), U1–2 Ex 1 (photo f): Tomas Rodriguez/Corbis; U1 Ex 2 (photo c), U1–2 Ex 4 (photo c): PeopleImages/DigitalVision; U1 Ex 2 (photo e): Jill Tindall/Moment; U1 Ex 2 (photo f), U1–2 Ex 4 (photo e): Jose manuel Gelpi diaz/Hemera/Getty Images Plus; U1 Ex 3 (photo a): thawats/iStock/Getty Images Plus; U1 Ex 3 (photo b): Lane Oatey/Blue Jean Images; U1 Ex 3 (photo c): RusN/iStock/Getty Images Plus; U1 Ex 3 (photo d): Evan Kafka/The Image Bank; U1 Ex 3 (photo e), EOY Ex 1 (photo d): SerrNovik/iStock/Getty Images Plus; U1 Ex 3 (photo f): bobbieo/E+; U1 Ex 4: Digital Vision; U1 Ex 5 (photo a): fcafotodigital/iStock/Getty Images Plus; U1 Ex 5 (photo b): Adrin Gmez/EyeEm; U1 Ex 5 (photo c): Peter Dazeley/Photographer's Choice RF; U1 Ex 5 (photo d): narapornm/iStock/Getty Images Plus; U1 Ex 5 (photo e): Mrs_2015/RooM; U1 Ex 5 (photo f): Chris Sweatman/EyeEm; U2 Ex 1 (photo a), U2 Ex 2 (photo a), U1–2 Ex 5 (photo a), EOY Ex 2 (photo 3): Science Photo Library; U2 Ex 1 (photo b), U2 Ex 2 (photo b), U1–2 Ex 5 (photo d), EOY Ex 2 (photo 4): Andy Crawford/Dorling Kindersley; U2 Ex 1 (photo c), EOY Ex 2 (photo 2): juliedeshaies/iStock/Getty Images Plus; U2 Ex 1 (photo d): matka_Wariatka/iStock/Getty Images Plus; U2 Ex 2 (photo c), U1–2 Ex 5 (photo e): mrPliskin/iStock/Getty Images Plus; U2 Ex 2 (photo d), U1–2 Ex 5 (photo b), EOY Ex 2 (photo 5): Cube/Ikon Images; U2 Ex 3: FatCamera/E+; U2 Ex 5 (photo a), U2 Ex 5 (photo e), U1–2 Ex 6 (proteins): Adam Gault/OJO Images; U2 Ex 5 (photo b), U1–2 Ex 6 (fruits and vegetables): Adrian Burke/Photographer's Choice; U2 Ex 5 (photo c), U1–2 Ex 6 (fats): Joy Skipper/Photolibrary; U2 Ex 5 (photo d): Jeffrey Coolidge/Stone; U2 Ex 6 (photo a): Walstrom, Susanne/Johner Images; U2 Ex 6 (photo b): energyy/E+; U2 Ex 6 (photo d): Flashpop/Taxi; U2 Ex 6 (photo e): Guerilla; U3 Ex 1 (photo a): Steven Kazlowski/Perspectives; U3 Ex 1 (photo b): Frederic Pacorel/Taxi; U3 Ex 1 (photo c): RedHelga/iStock/Getty Images Plus; U3 Ex 1 (photo d): Musat/iStock/Getty Images Plus; U3 Ex 1 (photo e), U3 Ex 4 (photo b), U3–4 Ex 6 (cows): Peter Cade/The Image Bank; U3 Ex 1 (photo f): Kim Taylor/Nature Picture Library; U3 Ex 2 (photo a): Patricia Doyle/Photographer's Choice; U3 Ex 2 (photo b): Sylvain Cordier/Biosphoto; U3 Ex 2 (photo c): DSW Creative Photography/Moment; U3 Ex 2 (photo d): Jerry Young/Dorling Kindersley; U3 Ex 2 (photo e): EcoPic/iStock/Getty Images Plus; U3 Ex 2 (photo f), U6 Ex 2 (photo e), U6 Ex 6 (photo b): CraigRJD/iStock/Getty Images Plus; U3 Ex 3 (photo a): Pascale Gueret/iStock/Getty Images Plus; U3 Ex 3 (photo b): Peter Chadwick LRPS/Moment; U3 Ex 3 (photo c): GlobalP/iStock/Getty Images Plus; U3 Ex 3 (photo d): Daniela Dirscherl/WaterFrame; U3 Ex 3 (photo e): Peter Hiscock/Dorling Kindersley; U3 Ex 4 (photo a): Patricia Hamilton/Moment; U3 Ex 4 (photo c): Marcia Straub/Moment; U3 Ex 4 (photo d), U3–4 Ex 3 (dandelions): Arterra/Universal Images Group; U3 Ex 4 (photo e), U3–4 Ex 2 (photo d), EOY Ex 3 (photo e): Visual China Group; U3 Ex 4 (photo f), U5 Ex 2 (photo 5): Fotosearch; U3 Ex 5: Reimphoto/iStock/Getty Images Plus; U4 Ex 1 (photo a), EOY Ex 4 (photo e): Stuart Minzey/Photographer's Choice RF; U4 Ex 1 (photo b): WIN-Initiative/Neleman; U4 Ex 1 (photo c), U5 Ex 6 (clouds), U6 Ex 2 (photo d), U5–6 Ex 6 (clouds): Tetra images; Dave King Dorling Kindersley/Dorling Kindersley; U4 Ex 1 (photo e), EOY Ex 4 (photo b): DonNichols/E+; U4 Ex 1 (photo f): DirkRietschel/iStock/Getty Images Plus; U4 Ex 2 (photo a): Mandy Disher Photography/Moment; U4 Ex 2 (photo b): Johner Images; U4 Ex 2 (photo c): DrPAS/iStock/Getty Images Plus; U4 Ex 2 (photo d): Photographer Chris Archinet/Moment; U4 Ex 2 (photo e): Christian Kunde/EyeEm; U4 Ex 2 (photo f), EOY Ex 4 (photo c): Antagain/iStock/Getty Images Plus; U4 Ex 3 (photo a), U3–4 Ex 3 (strawberry plant): lzf/iStock/Getty Images Plus; U4 Ex 3 (photo b): Andrea Edwards/EyeEm; U4 Ex 3 (photo d): lillisphotography/E+; U4 Ex 3 (photo e): dhughes9/iStock/Getty Images Plus; U4 Ex 3 (photo f): Matt Goldyn/EyeEm; U4 Ex 5: FrankRamspott/DigitalVision Vectors; U5 Ex 2 (photo 1): Dianne Avery Photography/Moment; U5 Ex 2 (photo 2), U5–6 Ex 3 (baby gorilla): Justin Sullivan/Getty Images News; U5 Ex 2 (photo 3): Jade Albert Studio, Inc/Photographer's Choice; U5 Ex 2 (photo 4): DNY59/E+; U5 Ex 2 (photo 6), U5–6 Ex 3 (growing plant): Foap AB/foap; U5 Ex 3 (photo a): simonkr/iStock/Getty Images Plus; U5 Ex 3 (photo b), U5 Ex 5 (photo c), U5–6 Ex 2 (photo d): alvarez/E+; U5 Ex 3 (photo c), U5–6 Ex 1 (photo f): Lee Pengelly/The Image Bank; U5 Ex 3 (photo d): Samir Belhocine/EyeEm; U5 Ex 3 (photo e), U5–6 Ex 3 (old gorilla): Dean Fikar/Moment; U5 Ex 3 (photo f): GK Hart/Vikki Hart/Stockbyte; U5 Ex 5 (photo a): Moncherie/E+; U5 Ex 5 (photo b), U5–6 Ex 3 (mummy gorilla): James D. Morgan/Getty Images News; U5 Ex 5 (photo d): David Woolley/DigitalVision; U5 Ex 6 (sand): Kevin Button/Moment; U5 Ex 6 (air): Adam Burton/robertharding; U5 Ex 6 (puppy and Kitten): dlillc/Corbis/VCG/Corbis Documentary; U5 Ex 6 (girl): Topic Images Inc.; U5 Ex 6 (tree), U5–6 Ex 1 (photo c): Charles Bowman/Perspectives; U5 Ex 6 (puppy), U5–6 Ex 1 (photo a): Colin Gray/Photonica; U6 Ex 1 (share): dobok/iStock/Getty Images Plus; U6 Ex 1 (kind): JGI/Jamie Grill/Blend Images; U6 Ex 1 (help), EOY Ex 6: Simon Winnall/Taxi; U6 Ex 1 (opinion): Steve Debenport/E+; U6 Ex 1 (clever): BSIP/Universal Images Group; U6 Ex 2 (photo b), U5–6 Ex 5 (photo 2): Wavebreakmedia/iStock/Getty Images Plus; U6 Ex 2 (photo c): J and J Productions/DigitalVision; U6 Ex 3 (photo a): StHelena/iStock/Getty Images Plus; U6 Ex 3 (photo b): RUSS ROHDE/Cultura; U6 Ex 3 (photo c): quavondo/E+; U6 Ex 3 (photo d): bradleym/E+; U6 Ex 3 (photo e): PHOTOSTOCK-ISRAEL/SCIENCE PHOTO LIBRARY; U6 Ex 3 (photo f): Denkou Images/Cultura; U6 Ex 6 (photo a): Maskot; U6 Ex 6 (photo c): Hill Street Studios/Blend Images; U6 Ex 6 (photo e), U1–2 Ex 2, U5–6 Ex 5 (photo 4): BJI/Blue Jean Images; U6 Ex 6 (photo f), U5–6 Ex 5 (photo 3): monkeybusinessimages/iStock/Getty Images Plus; U1–2 Ex 4 (photo a): Safia Fatimi/The Image Bank; U1–2 Ex 4 (photo b): Michael Heim/EyeEm; U1–2 Ex 4 (photo d): Lolkaphoto/iStock/Getty Images Plus; U1–2 Ex 5 (photo f): Rosemary Calvert/Photographer's Choice; U1–2 Ex 6 (sandwich): Creative Crop/DigitalVision; U1–2 Ex 6 (dinner): Brian Macdonald/DigitalVision; U3–4 Ex 1 (photo a): Kristian Bell/Moment; U3–4 Ex 1 (photo b): JVP photography/Moment; U3–4 Ex 1 (photo c): James Hager/robertharding; U3–4 Ex 1 (photo d): Mint Images/Mint Images RF; U3–4 Ex 1 (photo e): Rodrigo Friscione/Image Source; U3–4 Ex 1 (photo f), U3–4 Ex 6 (bird): copyright kengoh8888/Moment; U3–4 Ex 2 (photo a), EOY Ex 3 (photo d): PhotoAlto/Odilon Dimier/PhotoAlto Agency RF Collections; U3–4 Ex 2 (photo b), EOY Ex 3 (photo a): DEA/R. VALTERZA/De Agostini; U3–4 Ex 2 (photo c), EOY Ex 2 (photo 1), EOY Ex 3 (photo b): DEA/C.DANI/De Agostini; U3–4 Ex 2 (photo e), EOY Ex 3 (photo c): LEMAIRE Stephane/hemis.fr; U3–4 Ex 3 (lettuce): etiennevoss/iStock/Getty Images Plus; U3–4 Ex 3 (chamomile field): Martin Ruegner/Photographer's Choice; U3–4 Ex 3 (desk and chair): TongRo Images Inc/TongRo Images; U3–4 Ex 3 (aloe vera): Dorling Kindersley; U3–4 Ex 3 (television): scanrail/iStock/Getty Images Plus; U3–4 Ex 3 (wardrobe), U3–4 Ex 6 (furniture): Kate Davis/Dorling Kindersley; U3–4 Ex 3 (trouser): penguenstok/E+; U3–4 Ex 3 (bag): artisteer/iStock/Getty Images Plus; U3–4 Ex 3 (t-shirt): wragg/iStock/Getty Images Plus; U3–4 Ex 6 (wild plants): Luca Aragn/EyeEm; U3–4 Ex 6 (balloon fish): Dave Fleetham/Perspectives; U3–4 Ex 6 (watering can), U5–6 Ex 6 (watering can): David Burton/Photolibrary; U5–6 Ex 1 (photo b): Atomic Imagery/DigitalVision; U5–6 Ex 1 (photo d): Robert Alexander/Archive Photos; U5–6 Ex 1 (photo e), U5–6 Ex 6 (baby): Siri Stafford/Stone; U5–6 Ex 2 (photo a), U5–6 Ex 3 (plant): Allan Guiang/FOAP; U5–6 Ex 2 (photo b): Kate Jacobs/DigitalVision; U5–6 Ex 2 (photo c), U5–6 Ex 3 (dying flower): Milan Tarlac/EyeEm; U5–6 Ex 2 (photo e): Monashee Alonso/Caiaimage; U5–6 Ex 2 (photo f), U5–6 Ex 3 (sunflowers), U5–6 Ex 6 (sunflowers): Ana Maria Serrano/EyeEm; U5–6 Ex 3 (adult gorilla): atosan/iStock/Getty Images Plus; U5–6 Ex 5 (photo 1): JGI/Jamie Grill; U5–6 Ex 6 (lion): Andreygudkov/iStock/Getty Images Plus; U5–6 Ex 6 (windy): Bethany Lysaght/EyeEm; EOY Ex 4 (photo a): Image Source; EOY Ex 4 (photo d): DEA/G. WRIGHT/De Agostini.

Illustration by Michael Buxton (Advocate Art), Gaby Zermeño, Juan Antonio Cuesta.

Extension

Photo acknowledgements

All the photographs are sourced from Getty Images.

U1 Ex 1 (photo a), U1 Ex 2 (photo b), U1 Ex 2 (photo e), U1 Ex 6 (photo c), U1–2 Ex 1 (photo a): Yulia-Images/iStock/Getty Images Plus; U1 Ex 1 (photo b), U6 Ex 1, EOY Ex 1 (photo d): Hero Images; U1 Ex 1 (photo c), EOY Ex 1 (photo b): Sebastian Kaulitzki/Science Photo Library; U1 Ex 1 (photo d), U2 Ex 6 (photo c), U2 Ex 6 (photo d), EOY Ex 1 (photo e): KidStock/Blend Images; U1 Ex 1 (photo e), EOY Ex 1 (photo c): Monsterstock1/iStock/Getty Images Plus; U1 Ex 1 (photo f), U6 Ex 6 (photo d), U1–2 Ex 1 (photo c): Westend61; U1 Ex 1 (photo g), U1 Ex 2 (photo c), U1–2 Ex 1 (photo d), EOY Ex 1 (photo a): Thomas Barwick/DigitalVision; U1 Ex 2 (photo a): Peter Augustin/Stone; U1 Ex 2 (photo b), U1–2 Ex 1 (photo f): Tomas Rodriguez/Corbis; U1 Ex 2 (photo d): Jill Tindall/Moment; U1 Ex 3 (photo a): thawats/iStock/Getty Images Plus; U1 Ex 3 (photo c), U1–2 Ex 4 (photo e): RusN/iStock/Getty Images Plus; U1 Ex 3 (photo d), EOY Ex 1 (photo f): Evan Kafka/The Image Bank; U1 Ex 3 (photo e), EOY Ex 1 (photo g): SerrNovik/iStock/Getty Images Plus; U1 Ex 3 (photo f): bobbieo/E+; U1 Ex 4: Digital Vision; U1 Ex 5 (photo a): fcafotodigital/iStock/Getty Images Plus; U1 Ex 5 (photo b): narapornm/iStock/Getty Images Plus; U1 Ex 5 (photo c): Peter Dazeley/Photographer's Choice RF; U1 Ex 5 (photo d): Hans Georg Roth/Corbis Documentary; U1 Ex 5 (photo e): Chris Sweatman/EyeEm; U2 Ex 1 (photo a): Seb Oliver/Cultura; U2 Ex 1 (photo b), U2 Ex 1 (photo d), U2 Ex 2 (photo a), U2 Ex 2 (photo f), U1–2 Ex 5 (donut), EOY Ex 2 (photo c): Science Photo Library; U2 Ex 1 (photo c), U2 Ex 2 (photo b), U1–2 Ex 5 (yoghurt), EOY Ex 2 (photo d): Andy Crawford/Dorling Kindersley; U2 Ex 1 (photo e), EOY Ex 2 (photo b): juliedeshaies/iStock/Getty Images Plus; U2 Ex 1 (photo f): Dave King Dorling Kindersley; U2 Ex 2 (photo c), U1–2 Ex 5 (pear), EOY Ex 2 (photo e): Cube/Ikon Images; U2 Ex 2 (photo d), U1–2 Ex 5 (crisps), EOY Ex 2 (photo a): mrPliskin/iStock/Getty Images Plus; U2 Ex 2 (photo e): James A. Guilliam/Photolibrary; U2 Ex 3: FatCamera/E+; U2 Ex 5 (photo a), U2 Ex 5 (photo e): Adam Gault/OJO Images; U2 Ex 5 (photo b): Adrian Burke/Photographer's Choice; U2 Ex 5 (photo c): Joy Skipper/Photolibrary; U2 Ex 5 (photo d): Jeffrey Coolidge/Stone; U2 Ex 6 (photo a): Walstrom, Susanne/Johner Images; U2 Ex 6 (photo b): energyy/E+; U2 Ex 6 (photo d): Flashpop/Taxi; U2 Ex 6 (photo e): Guerilla; U3 Ex 1 (photo a): Steven Kazlowski/Perspectives; U3 Ex 1 (photo b): Frederic Pacorel/Taxi; U3 Ex 1 (photo c): RedHelga/iStock/Getty Images Plus; U3 Ex 1 (photo d): Musat/iStock/Getty Images Plus; U3 Ex 1 (photo e), U3 Ex 4 (photo b), U3–4 Ex 6 (cows), Peter Cade/The Image Bank; U3 Ex 1 (photo f), U3 Ex 1 (butterfly): Kim Taylor/Nature Picture Library; U3 Ex 2 (photo a): Patricia Doyle/Photographer's Choice; U3 Ex 2 (photo b): Sylvain Cordier/Biosphoto; U3 Ex 2 (photo c): DSW Creative Photography/Moment; U3 Ex 2 (photo d): Jerry Young/Dorling Kindersley; U3 Ex 2 (photo e): EcoPic/iStock/Getty Images Plus; U3 Ex 2 (photo f), U6 Ex 6 (photo b): CraigRJD/iStock/Getty Images Plus; U3 Ex 3 (balloon fish): Wild Horizon/Universal Images Group; U3 Ex 3 (frog): Pascale Gueret/iStock/Getty Images Plus; U3 Ex 3 (hen): Peter Chadwick LRPS/Moment; U3 Ex 3 (horse): GlobalP/iStock/Getty Images Plus; U3 Ex 3 (shark): Daniela Dirscherl/WaterFrame; U3 Ex 3 (crocodile): Peter Hiscock/Dorling Kindersley; U3 Ex 4 (photo a): Patricia Hamilton/Moment; U3 Ex 4 (photo c): Marcia Straub/Moment; U3 Ex 4 (photo d), U4 Ex 3 (photo c): Arterra/Universal Images Group; U3 Ex 4 (photo e), U3–4 Ex 2 (photo e), EOY Ex 3 (photo e): Visual China Group; U3 Ex 4 (photo f): Fotosearch; U3 Ex 5: Reimphoto/iStock/Getty Images Plus; U4 Ex 1 (photo a), EOY Ex 4 (seeds): Stuart Minzey/Photographer's Choice RF; U4 Ex 1 (photo b), EOY Ex 4 (flower): WIN-Initiative/Neleman; U4 Ex 1 (photo c), U5 Ex 6 (clouds), U5–6 Ex 6 (clouds): Tetra images; U4 Ex 1 (photo d), U3–4 Ex 6 (leaves), EOY Ex 4 (leaves): Dave King Dorling Kindersley/Dorling Kindersley; U4 Ex 1 (photo e), EOY Ex 4 (roots): DonNichols/E+; U4 Ex 1 (photo f): DirkRietschel/iStock/Getty Images Plus; U4 Ex 3 (photo a): lzf/iStock/Getty Images Plus; U4 Ex 3 (photo b): Andrea Edwards/EyeEm; U4 Ex 3 (photo d): lillisphotography/E+; U4 Ex 3 (photo e): dhughes9/iStock/Getty Images Plus; U4 Ex 3 (photo f): Matt Goldyn/EyeEm; U4 Ex 5: FrankRamspott/DigitalVision Vectors; U5 Ex 2 (photo a): Dianne Avery Photography/Moment; U5 Ex 2 (photo b): Justin Sullivan/Getty Images News; U5 Ex 2 (photo c): Juice Images/Cultura; U5 Ex 3 (photo a): simonkr/iStock/Getty Images Plus; U5 Ex 3 (photo b), U5–6 Ex 2 (photo d): alvarez/E+; U5 Ex 3 (photo c), U5–6 Ex 1 (photo f): Lee Pengelly/The Image Bank; U5 Ex 3 (photo d): Samir Belhocine/EyeEm; U5 Ex 3 (photo e): GK Hart/Vikki Hart/Stockbyte; U5 Ex 5 (photo a): Moncherie/E+; U5 Ex 5 (photo b): James D. Morgan/Getty Images News; U5 Ex 5 (photo c), U5–6 Ex 2 (photo b): Kate Jacobs/DigitalVision; U2 Ex 6 (photo e), U5–6 Ex 6 (girl): LWA/Dann Tardif/Blend Images; U5 Ex 5 (photo f): David Woolley/DigitalVision; U5 Ex 6 (sand): Kevin Button/Moment; U5 Ex 6 (air): Adam Burton/robertharding; U5 Ex 6 (water): myshkovsky/iStock/Getty Images Plus; U5 Ex 6 (puppy and Kitten): DLILLC/Corbis/VCG/Corbis Documentary; U5 Ex 6 (girl): Topic Images Inc.; U5 Ex 6 (tree), U5–6 Ex 1 (photo b): Charles Bowman/Perspectives; U5 Ex 6 (puppy), U5–6 Ex 1 (photo a): Colin Gray/Photonica; U5 Ex 6 (baby), U5–6 Ex 1 (photo c), U5–6 Ex 6 (baby): Siri Stafford/Stone; U6 Ex 3 (photo a): StHelena/iStock/Getty Images Plus; U6 Ex 3 (photo b): RUSS ROHDE/Cultura; U6 Ex 3 (photo c): quavondo/E+; U6 Ex 3 (photo d): bradleym/E+; U6 Ex 3 (photo e): Photostock-Israel/Science Photo Library; U6 Ex 3 (photo f), U5–6 Ex 4: Denkou Images/Cultura; U6 Ex 4 (putting books): Ruth Jenkinson/Dorling Kindersley; U6 Ex 4 (calmly): Andersen Ross/Blend Images; U6 Ex 4 (tidy bed): JGI/Jamie Grill/Blend Images; U6 Ex 4 (nice): Sam Edwards/Stone; U6 Ex 4 (tidy room): Johner Images; U6 Ex 6 (photo a): Maskot; U6 Ex 6 (photo c): Hill Street Studios/Blend Images; U6 Ex 6 (photo e), U1–2 Ex 2, U5–6 Ex 5 (photo d): BJI/Blue Jean Images; U6 Ex 6 (photo f), U5–6 Ex 5 (photo c): monkeybusinessimages/iStock/Getty Images Plus; U1–2 Ex 4 (photo a): Safia Fatimi/The Image Bank; U1–2 Ex 4 (photo b): Michael Heim/EyeEm; U1–2 Ex 4 (photo c): Lolkaphoto/iStock/Getty Images Plus; U1–2 Ex 4 (photo d): PeopleImages/DigitalVision; U1–2 Ex 4 (photo f): Jose manuel Gelpi diaz/Hemera/Getty Images Plus; U1–2 Ex 5 (milk): alisafarov/iStock/Getty Images Plus; U1–2 Ex 6: Okea/iStock/Getty Images Plus; U3–4 Ex 1 (snake): Kristian Bell/Moment; U3–4 Ex 1 (crab): JVP photography/Moment; U3–4 Ex 1 (fox): James Hager/robertharding; U3–4 Ex 1 (jellyfish): Mint Images/Mint Images RF; U3 Ex 1 (butterfly): Kim Taylor/Nature Picture Library; U3–4 Ex 1 (dolphin: Rodrigo Friscione/Image Source; U3–4 Ex 1 (bird), U3–4 Ex 6 (bird): copyright kengoh8888/Moment; U3–4 Ex 2 (photo a), EOY Ex 3 (photo d): PhotoAlto/Odilon Dimier/PhotoAlto Agency RF Collections; U3–4 Ex 2 (photo b), EOY Ex 3 (photo b): DEA/C.DANI/De Agostini; U3–4 Ex 2 (photo c), EOY Ex 3 (photo a): LEMAIRE Stephane/hemis.fr; U3–4 Ex 2 (photo d), EOY Ex 3 (photo c): DEA/R. VALTERZA/De Agostini; U3–4 Ex 3 (photo a): antigonigoni/iStock/Getty Images Plus; U3–4 Ex 3 (photo b): Ryan Malensek/EyeEm; U3–4 Ex 3 (photo c): dszc/E+; U3–4 Ex 3 (photo d): Martin Ruegner/Photographer's Choice; U3–4 Ex 6 (wardrobe): Kate Davis/Dorling Kindersley; U3–4 Ex 6 (windy), U5–6 Ex 6 (windy): Bethany Lysaght/EyeEm; U3–4 Ex 6 (wild plants): Luca Aragn/EyeEm; U3–4 Ex 6 (balloon fish): Dave Fleetham/Perspectives; U3–4 Ex 6 (watering can), U5–6 Ex 6 (watering can): David Burton/Photolibrary; U5–6 Ex 1 (photo d): Atomic Imagery/DigitalVision; U5–6 Ex 1 (photo e): Robert Alexander/Archive Photos; U5–6 Ex 2 (photo a): Allan Guiang/FOAP; U5–6 Ex 2 (photo c): Milan Tarlac/EyeEm; U5 Ex 2 (photo e): Jade Albert Studio, Inc/Photographer's Choice; U5–6 Ex 2 (photo f), U5–6 Ex 6 (sunflowers): Ana Maria Serrano/EyeEm; U5–6 Ex 5 (photo a): JGI/Jamie Grill; U5–6 Ex 5 (photo b): Wavebreakmedia/iStock/Getty Images Plus; U5–6 Ex 6 (lion): ANDREYGUDKOV/iStock/Getty Images Plus; U5–6 Ex 3 (growing plant): Foap AB/foap; EOY Ex 4 (trunk): Christian Kunde/EyeEm; EOY Ex 4 (grass): DEA/G. WRIGHT/De Agostini; EOY Ex 4 (woody): Antagain/iStock/Getty Images Plus; EOY Ex 4 (tree): Image Source; EOY Ex 6: Simon Winnall/Taxi.

Illustration by Michael Buxton (Advocate Art), Gaby Zermeño, Juan Antonio Cuesta.