extra

• bacteria in soil respire and produce carbon dioxide -> use plastic bag around soil to prevent carbon dioxide from reaching soil
• chlorplasts absorb light energy (not just solar)
• heat filter water in a light intensity experiment so that only the light is tested
• state how stoma and cuticle are involved in the control of water loss from a leaf

  stoma = stoma closes when the guard cell has lost too much water to reduce water loss

  cuticle = secretes a waxy layer to reduce water loss
• suggest two advantages of growing plants in water rather than soil

  1. plants need less space
  2. no weeds
  3. no pests
• water will evaporate if left out in open unprotected