CIE iGCSE Co-Ordinated Science B19.1 Habitat destruction Exam Style Questions Paper 4
Question
Scientists investigate eutrophication in a lake.
They measure the relative abundance of different factors.
Fig. 10.1 is a graph summarising the results.
(a) The growth of surface producers in the lake increases during eutrophication.
Explain why, using the information in Fig. 10.1.
(b) The number of underwater producers in the lake decreases during eutrophication.
Explain why, using the information in Fig. 10.1.
(c) State the name of the type of organisms that cause the change in dissolved oxygen in the lake in Fig. 10.1.
▶️Answer/Explanation
Ans : 10(a) increase in nitrates ;
(increased) production of, amino acids / proteins (for growth) ;
10(b) decrease in light (availability) ;
so less / no, photosynthesis (so underwater producers die) ;
10(c) bacteria / decomposers ;