In an investigation, individual Rhabdostyla were placed into different concentrations of sea water.
The rate of water excreted by the contractile vacuðle of each organism was determined. The results
are shown in Fig. 4.2.
20
18-
16
[3]
14
12
rate of
water
excreted
um's
10
8-
6
4-
2
0
0
4
12
Explain the result