(a(i))[4]
Complete Fig. 6.1 by choosing from the words in the list to label these structures on the answer lines given.
(a(ii))[2]
State the names of two structures in the cell shown in Fig. 6.1 that are absent from animal cells.
(a(iii))[1]
Describe what plasmids do in bacterial cells.
(b)[2]
Explain why producing and using methane in this way can be described as sustainable.
(c)[3]
Describe how untreated sewage affects river ecosystems.