MCQ-1: Human Influences on Ecosystems

The diagrams show the current population sizes for people below 50 years of age in four different countries.
Which country will be likely to have the largest population of people 60 – 70 years of age in 20 years time?

What makes nuclear fall-out dangerous to living organisms?

A very large area of land has been cleared of rainforest and planted with soybean.
What result of deforestation will encourage the growth of the soybean plants?

The map shows a river flowing into the sea. The river is polluted by untreated sewage.
At which labelled point will the oxygen content of the water be lowest?

Some bacteria were grown in a nutrient solution over a period of two weeks. The graph shows how the population of bacteria changed during this time.
Which is the lag phase in the growth of this population?

Weeds are growing in a crop.
What should be used to kill the weeds?

A large area is heavily overgrazed for many years.
How does this affect soil nutrients and soil erosion?

The diagram shows some of the effects of human activity on a river.

What could have caused these effects?

In an ecosystem, which are the only organisms to remove carbon dioxide from the atmosphere?

What name is given to the diagram below?

The diagram shows the results of a survey on the types of animals found along a stretch of river near to a factory.

Which of the following animals lives in the most polluted water?

The graph shows how oxygen concentration and the number of bacteria change when sewage is added to a river.

What describes the oxygen concentration and the number of bacteria between the point at which sewage is added and point P?

On the map shown, sulfur dioxide is produced at X. Which region is most likely to experience acid rain?

The diagram shows how the size of a population may change with time.
At which point is the population growing the fastest?

Which agricultural activity can cause the most pollution?

The graph shows the levels of dissolved oxygen and mineral ions in a river.
At what point does raw sewage enter the river?

The bloodworm is found in heavily polluted water.
The diagram shows where raw sewage flows into a river.
Where would there be fewest bloodworms?

What describes eutrophication and its effect on a river?

Which letter represents the lag phase in the population graph shown?

The diagram shows part of the water cycle.

How is water lost from the tree?