Question 18M.2.SL.TZ1.1d
| Date | May 2018 | Marks available | [Maximum mark: 2] | Reference code | 18M.2.SL.TZ1.1d |
| Level | SL | Paper | 2 | Time zone | TZ1 |
| Command term | Deduce | Question number | d | 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.
The population of C. nemoralis has been studied for many years in open fields in a similar area. In the graph, each data point represents the percentage of adults of a given base colour plotted against the percentage of juveniles of the same base colour collected each year.
Deduce from the data in the graph which shell base colours are on average most and least frequent among adult snails.
Most frequent:
Least frequent:
[2]
a. brown most frequent
b. pink least frequent
