When the yeast starts to grow it produces carbon dioxide, which makes thebread rise by causing bubbles in the dough.
This is called decomposition. Keys will differ depending on information used bystudents. Answers to coursebook questions Chapter Various answers possible. Some examples are given below. Microbe type Benefits Problems and cost to societyBacteria Making foods such as yogurtand cheese. Decomposition of deadmaterial. Cause many diseases costingmillions of dollars each year andkilling people. Medical research is aimed atdeveloping new antibiotics all thetime.
Cause many diseases, costingmillions of dollars each year andkilling people. Protists Part of natural ecosystem. VirusesMay be used in geneticengineering and for treatingsome cancers. Medical research is aimed atdeveloping cures. Answers to coursebook questions Chapter 4Unit 4. Lipids are also a source ofenergy; margarine, vegetable oil. Proteins are needed for growth and repair of cells;meat, eggs. Vitamins speed up chemical reactions in the body and are required forgood health; fruit and vegetables.
Minerals are required for good health; milk,cereals. Scurvy may be caused bylack of vitamin C. Think19 Teenagers are growing at a more rapid rate and require higher levels of nutrientsthan adults. Analyse27 Diagrammatic answer required.
Skills29 Diagrammatic answer required. Unit 4. Answers to coursebook questions Chapter 4e Liver. Think22 There may be bile present, which is green. Create30 Diagrammatic answer required.
O represents theabsence of A and B antigens. The aorta walls expand andcontract as blood is pumped to help move it along. Blood passes from theatrium through valves to the ventricle. Blood is pumped from the heart to the lungs. Blood returns from thelungs to the heart. Blood is pumped out of the heart through the aorta main artery to the body. It passes through smaller and smaller arteries and vessels until itreaches the capillaries in the toe.
The nutrients pass out of the capillaries into thecells of the toe. Think18 In case they suffer an injury or have an operation requiring a blood transfusion—they know the blood is safe for them. Answers to coursebook questions Chapter Arteries carry blood away from the heart at high pressure, while veins allow bloodto drain back to the heart under low pressure. Think6 Diagrammatic answer required. See Figure 4. Filter blood. Allow urine to reach storage area. Urine storage. Tube which allows urine to leave the body.
At mL you feel the urge to urinate. Skills14 Diagrammatic answer required. Prevents food from entering the trachea.
To filter, warm and humidify air. To remove foreign particles from the lungs. The site of gas exchange. Answers to coursebook questions Chapter 4c Greater. The mouth does not dothis. Our ribs move upwards and outwards.
Analyse15 a Oxygen. Converted to glucose duringdigestion. Not a nutrient, but required for chemical reactions in the body. High in energy. Provides bulk to move waste through intestines. Required in small amounts for good health. Chemically simple, required for good health, not for energy. Root canal treatmentinvolves the sterilisation and filling of the pulp cavity.
Farmers can reverse the effects of acid rain on soil by adding the base calcium hydroxide. A tyre burst, sending fragments into the wing, puncturing the fuel tanks. Why can we not agree this just? No detail and a strip to be film. If a sodium atom meets a chlorine atom they will rearrange their electrons so that both can become more stable.
Connects mouth to stomach. Like a cement-mixer for food and gastricjuices. Produces enzymes including insulin. Stores bile.
Science Focus 3 Second Edition. The Expand All and Collapse All buttons require Chapter 3: Chemical Change. Level 1 indent Quick Quiz Level 1 indent . second edition Greg Rickard Isabella Brown Nici Burger Warrick Clarke Janette Ellis Faye Jeffery Caroline Jeffries Karin.
Start of small intestine. Where most absorption of nutrientsoccurs.
Where water is absorbed. Answers to coursebook questions Chapter Cholesterol. Thinking questions18 a We excrete when we breathe out. Various answers for menu. Glycogen can be stored in muscle tissue.
Answers vary with age. Answers to coursebook questions Chapter 5Unit 5. See Figure 5. Like charges repel each other, so hairattempts to move as far away from the head and other hair as possible. Standing on arubber mat prevents charge escaping through the floor and so aids charge build-up.