Pond weed was placed in five water-filled tubes and the experimental set up was allowed to remain as shown in the diagram alongside for 24 hours. In which tube would you expect to find:
(i) the greatest increase in the dry weight of the pond weed?
(ii) the plant with the least amount of starch?
(iii) the most oxygen?
(iv) the least carbon dioxide?
(v) the plant to survive for the longest length of time?
(i) Tube - 2
(ii) Tube - 5
(iii) Tube - 1
(iv) Tube - 1
(v) Tube - 2
(i) Tube - 2; because the snail provides carbon dioxide through its respiration and thus, more photosynthetic activity takes place.
(ii) Tube - 5; because the plant is in dark. So there willl be no photosynthesis.
(iii) Tube - 1; because it is in full light and no animal is present to utilize the oxygen released by the plant
(iv) Tube - 1; because no snail to release carbon dioxide and the plant is utilizing the existing gas.
(v) Tube - 2, It is because the snail can provide carbon dioxide for photosynthesis and it has got all requirements for its survival.