Question 21N.2.HL.TZ0.f
| Date | November 2021 | Marks available | [Maximum mark: 2] | Reference code | 21N.2.HL.TZ0.f |
| Level | HL | Paper | 2 | Time zone | TZ0 |
| Command term | Suggest | Question number | f | Adapted from | N/A |
In a larger study, California grassland was exposed to elevated temperature and nitrate concentration for five years. The graph shows the total biomass production in individual and in combined treatments. Error bars denote one standard error.
[Source: adapted from Dukes, J.S., Chiariello, N.R., Cleland, E.E., Moore, L.A., Shaw, M.R., Thayer,S., Tobeck, T.,
Mooney, H.A. and Field, C.B., 2005. PLOS Biology, 3(10), e319. https://doi.org/10.1371/journal.pbio.0030319.]
Suggest two abiotic factors, other than temperature and nutrient supply, that may affect the production of biomass of the grasslands.
[2]
a. water availability/rainfall/humidity;
b. light/sunlight (intensity) / daylength;
c. salinity of soil / high/low soil pH;
d. chemical pollution/herbicides/allelopathy/parasitic weeds;
Mark the first two answers only.
Do not accept carbon dioxide or weather conditions.
About half of answers given were accepted. Carbon dioxide concentration was unlikely to vary enough to affect grassland biomass production. Vague answers such as ‘pH’ were not accepted but soil pH was.
