The living world

1. Why is nutrient cycling fast in tropical rainforests?

1. Cold temperatures
2. Hot, wet conditions speed up decomposition
3. Few plants grow
4. Soils are very deep

Show answer

B: Hot, wet conditions speed up decomposition. Decomposers work rapidly in warm, humid conditions.

2. What mainly determines the distribution of biomes?

1. Population density
2. Climate
3. Political borders
4. Soil colour only

Show answer

B: Climate. Temperature and rainfall patterns are the key controls.

3. What are drip-tip leaves an adaptation to?

1. Cold nights
2. High rainfall, allowing water to run off quickly
3. Strong winds
4. Poor light

Show answer

B: High rainfall, allowing water to run off quickly. Water runs off, preventing damage and fungal growth.

4. Which is a cause of deforestation in the Amazon?

1. Ecotourism
2. Cattle ranching and commercial farming
3. Selective logging only
4. Replanting schemes

Show answer

B: Cattle ranching and commercial farming. Large areas are cleared for pasture and crops such as soya.

5. Which is a sustainable management strategy for rainforests?

1. Clear felling
2. Selective logging and replanting
3. Building more roads
4. Unregulated mining

Show answer

B: Selective logging and replanting. Only some trees are removed, allowing the forest to recover.

6. What is a food web?

1. A single food chain
2. A network of interconnected food chains in an ecosystem
3. A type of biome
4. A soil profile

Show answer

B: A network of interconnected food chains in an ecosystem. It shows how energy flows through many linked feeding relationships.

7. Which layer of a tropical rainforest is made up of the tallest trees, often over 40 m, that rise above the main canopy?

1. Under-canopy layer
2. Shrub layer
3. Forest floor
4. Emergent layer

Show answer

D: Emergent layer. Emergent trees poke above the closed canopy. They get full sunlight but are exposed to wind and heat. The shrub layer and forest floor are dark and low.

8. What is the main function of buttress roots in tropical rainforest trees?

1. To store water for the dry season
2. To absorb nutrients from deep in the soil
3. To shed heavy rain from the leaves
4. To support very tall trees in thin, shallow soils

Show answer

D: To support very tall trees in thin, shallow soils. Rainforest soils are thin, so tall trees have shallow roots. Wide, plank-like buttress roots spread the weight and stop the trees toppling over.

9. Which pair contains only biotic components of a rainforest ecosystem?

1. Soil and humidity
2. Sunlight and leaf litter
3. Jaguar and strangler fig
4. Rainfall and temperature

Show answer

C: Jaguar and strangler fig. Biotic means living. A jaguar and a fig tree are living organisms. Rainfall, temperature, sunlight, soil and humidity are abiotic (non-living).

10. Why do lianas grow as woody climbing plants in tropical rainforests?

1. To store water in their stems for the dry season
2. To protect themselves from grazing animals with spines
3. To shed heavy rainfall quickly from their leaves
4. To reach sunlight in the canopy without building thick trunks

Show answer

D: To reach sunlight in the canopy without building thick trunks. The forest floor is dark. Lianas climb tree trunks to reach light in the canopy, which saves the energy that tall self-supporting trunks would need.