IGCSE Biology Paper-3: Specimen Questions with Answers 250 - 252 of 358


shows a diagram of the heart.

Structure of Photosynthesis

Question 250 (3 of 4 Based on Passage)


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The condition where watery faeces are lost from the body is called diarrhea.

Outline one way in which diarrhea can be treated.


Treatment of Diarrhea

  • plenty of fluids to prevent dehydration
  • oral rehydration drinks to replace lost salts and minerals. These drinks are available from pharmacies. An alternative is one-part unsweetened pure fruit juice diluted with four parts of water

  • intravenous replacement of fluids in severe cases

  • medications such as antibiotics and anti-nausea drugs

  • anti-diarrheal medications, but only on the advice of your doctor. If your diarrhea is caused by infection, anti-diarrheal drugs may keep the infection inside your body for longer.

Question 251 (4 of 4 Based on Passage)


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Describe how the protein in food is digested in the alimentary canal.


Protein Food

Question 252


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HIV is an example of a sexually transmitted disease.

(i) Define the term sexually transmitted disease.

(ii) State the name of the disease that HIV can lead to.

(iii) Describe one other way that HIV can be transmitted.


Sexually Transmitted Diseases (STDS)

  • Diseases or infections which are transmitted through sexual intercourse are collectively called sexually transmitted diseases (STD) . Also called venereal diseases (VD) or reproductive tract infections (RTI) . Gonorrhoea, syphilis, genital herpes, chlamydiasis, genital warts, trichomoniasis, hepatitis-B, HIV leading to AIDS are some of the common STDs. Among these, HIV infection is most dangerous.
  • Human Immunodeficiency Virus (HIV) causes an infection that damages the immune system. The immune system is the part of the body that fights infection and disease. If untreated, HIV infection will lead to a serious disease called Acquired Immunodeficiency Syndrome (AIDS) .

HIV can only be spread through specific activities:

  • Having vaginal sex with someone who has HIV.

  • Receiving blood transfusions, blood products, or organ/tissue transplants that are contaminated with HIV.

  • Getting stuck with an HIV-contaminated needle.

  • From mother to child during pregnancy, birth, or breastfeeding.

  • Contact between broken skin, wounds, or mucous membranes and HIV-infected blood or blood-contaminated body fluids.

  • Deep, open-mouth kissing if both partners have sores or bleeding gums and blood from the HIV-positive partner gets into the bloodstream of the HIV-negative partner. HIV is not spread through saliva.

  • Eating food that has been pre-chewed by a person with HIV.