| Date | May 2013 | Marks available | 1 | Reference code | 13M.1.SL.TZ1.5 |
| Level | Standard level | Paper | Paper 1 | Time zone | Time zone 1 |
| Command term | Question number | 5 | Adapted from | N/A |
Question
Water shows strong cohesive properties. Which of the following can occur because of the cohesive properties of water?
A. Water can be pulled up a plant through the xylem.
B. Enzymes can react with their substrates in cells.
C. Sweating cools the body on a hot day.
D. Salt can dissolve in sea water.
Markscheme
A
Examiners report
Question 5 included the term xylem, which is not specifically mentioned in the SL Biology programme, but Assessment Statement 3.1.6 indicates that candidates should understand the relationship between water’s properties and its use as a transport medium. These include water’s cohesive properties and thus its movement under tension in plant transport. Even if candidates were uncertain whether the answer including xylem was correct, they should have been able to eliminate the other three alternatives. More than 75% of candidates answered this question correctly and the discrimination index was high.
