Question 18M.2.SL.TZ1.b
| Date | May 2018 | Marks available | [Maximum mark: 1] | Reference code | 18M.2.SL.TZ1.b |
| Level | SL | Paper | 2 | Time zone | TZ1 |
| Command term | Suggest | Question number | b | Adapted from | N/A |
The land snail Cepaea nemoralis is very common in North America and in Europe.
The base colour of its shell varies between brown, pink and yellow, and also in its intensity. Some shells are unbanded, but most show one to five bands of different width on top of the shell base colour.
In the early 1950s, scientists studied the proportion of colours and banding of C. nemoralis in woods and fields near Oxford, UK, which differed in the type of plants and background colour. Each data point on the graph represents the percentage of yellow base colour shells and unbanded shells in a sample from either one type of wood or field, although other snail colours were present.
Suggest either one possible advantage or one disadvantage of having a banded shell, stating whether it is an advantage or disadvantage.
[1]
advantage: camouflage
OR
disadvantage: visibility
