Life Processes — Questions & Answers

Sample questions from Life Processes

1. Q1. The main products absorbed after carbohydrate digestion are:

   • A.simple sugars✓
   • B.amino acids only
   • C.fatty acids only
   • D.urea
   Solution

   Carbohydrates are digested into simple sugars such as glucose.

2. Q2. The opening and closing of a stoma is controlled by:

   • A.water entering or leaving the guard cells, changing their shape✓
   • B.the amount of chlorophyll in the leaf
   • C.the thickness of the cuticle
   • D.the number of veins in the leaf
   Solution

   Guard cells swell when water enters and their unevenly thickened walls curve apart, opening the pore; losing water makes them limp and the pore closes. This is how a plant limits water loss when transpiration would be too costly.

3. Q3. Plants get rid of many of their waste products by:

   • A.Excreting them through specialised kidney-like organs
   • B.Storing them as gums and resins in old xylem, or losing them in falling leaves✓
   • C.Releasing them as urea through the stomata
   • D.Passing all of them into the phloem sap for storage in roots
   Solution

   Plants have no excretory organs; wastes are stored as resins and gums in old xylem, deposited in leaves that are shed, or released into the soil.

4. Q4. Observation 7: A high concentration of carbon dioxide in blood generally causes:

   • A.faster breathing✓
   • B.no respiration
   • C.starch formation
   • D.urine storage only
   Solution

   The respiratory centre increases ventilation to remove excess CO₂.

5. Q5. The organ used for gaseous exchange in humans is the:

   • A.lungs✓
   • B.kidneys
   • C.heart
   • D.liver
   Solution

   Lungs exchange oxygen and carbon dioxide.

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