Ethiopia Grade 12 Biology: Unit 2 (The ecology and uses of bacteria) Question Answers

Ethiopia Grade 12 Biology: Unit 2 Ecology Question Answers: Unit 2 (The ecology and uses of bacteria) Question Answers for Ethiopian University Entrance exam. This page contains multiple choice question answers.

By the end of this section you should be able to: Explain the need for the recycling of materials through ecosystems. Illustrate the nutrient cycle. Describe and diagram the water, carbon, nitrogen, sulphur and phosphorus cycles. State that materials do not always remain within an ecosystem

Unit 2 Ecology Question Answers

Cycling matter through ecosystems
Ecological succession
Biomes
Biodiversity
Populations

Ethiopia Grade 12 Biology: Unit 2 Ecology Question Answers

Ethiopia Grade 12
Subject: Biology
Unit No: 2
Topics: Ecology

Total Questions: 35
Answers Available: YES
Explanation: Yes

1 / 35

Phosphate is absorbed from the soil (or water) by plants.

A) True

B) False

2 / 35

How are fossil fuels formed?

A) during fossilisation process

B) during de-fossilisation process

C) during respiration process

D) during combustion process

3 / 35

In an ecological succession:

A) pioneer species are the first to colonise an area

B) the most complex community to develop is the climax community

C) each stage in the succession alters the environment so that other species can enter

D) all of the above

4 / 35

What is abiotic?

A) describes the living part of an ecosystem

B) describes the non-living part of an ecosystem

C) describes the chemical part of an ecosystem

D) none of the above

5 / 35

The final, most complex, state of succession is the ______ community.

A) climax

B) abiotic

C) scrub stage

D) perennial herb stage

6 / 35

Decomposers feed by:

A) parasitic nutrition

B) saprobiotic nutrition

C) intracellular digestion

D) autotrophic nutrition

7 / 35

What is the first stage in the nitrogen cycle?

A) the nitrates are then used to form amino acids, which are used to synthesise proteins

B) both plants and animals die

C) plants absorb nitrates from the soil

D) the plants are eaten by animals

8 / 35

Which of the following organisms could not synthesise without nitrogen?

A) their genetic material (DNA)

B) their principal structural materials (proteins)

C) their principal energy transfer molecule (ATP)

D) all of the above

9 / 35

A secondary succession differs from a primary succession to the same climax in that:

A) it usually takes a greater period of time

B) it requires no pioneer species

C) there is an existing seed bank to draw on

D) it starts from ground that has never been colonised

10 / 35

The stages in a succession are referred to as:

A) pioneers

B) seres

C) climaxes

D) communities

11 / 35

Which of the following is released by the decomposers?

A) mineral elements

B) nitrogen

C) phosphorus

D) all of the above

12 / 35

In the nitrogen cycle, nitrogen gas is returned to the atmosphere by:

A) nitrogen-fixing bacteria

B) ammonifying bacteria/decomposers

C) nitrifying bacteria

D) denitrifying bacteria

13 / 35

Which of the following process used by fungi to obtain nutrients from nonliving organic matter?

A) Extracellular digestion

B) Saprobiontic

C) Fossilisation

D) Combustion

14 / 35

Which of the following statements about the nitrogen cycle is true?

A) Plants fix nitrates into atmospheric nitrogen

B) All the nitrogen obtained by animals came from plants.

C) Nitrogen is consumed by bacteria and removed from the soil

D) Nitrogen-fixing bacteria reduce the total amount of available nitrogen in the nitrogen cycle.

15 / 35

Which of the following is a legume plant?

A) beans

B) lentils

C) peas

D) all of the above

16 / 35

Which of the following is an organism that breaks down dead organic matter and recycles it?

A) Detritus

B) Decomposers

C) Carnivores

D) Organic material

17 / 35

Secondary successions to the original climax are usually much quicker than primary successions because

A) the succession is starting from bare rock/open water

B) there is no seed bank of many of the climax plant types available in remaining undamaged plants

C) the soil is already present

D) all of the above

18 / 35

In the sulphur cycle, hydrogen sulphide is oxidised to sulphur by:

A) photosynthetic sulphur bacteria

B) Desulphovibrio

C) Thiobacillus

D) none of the above

19 / 35

Which of the following comparisons of the phosphorus and carbon cycles is true?

A) The biological components of the cycles involve recycling through the atmosphere.

B) The non-biological components involve the use of fossil fuels by humans.

C) The non-biological components involve the agriculture industry

D) The biological components involve feeding, death and decomposition.

20 / 35

Which of the following statements concerning the water cycle are true?

A) Aquifers are large underground natural reservoirs.

B) Evaporation uses energy from the sun to vaporise liquid water.

C) Run-off is the movement of water along the surface

D) All of the above

21 / 35

Which of the following is the best explanation for the fact that decomposers are found in the carbon, nitrogen, sulphur and phosphorus cycles?

A) They digest organic molecules.

B) They feed on dead materials.

C) They release mineral ions that are combined in complex organic molecules

D) They decay dead materials

22 / 35

Which of the following factors does not affect the type of climax community that develops?

A) temperature

B) the presence of grazing animals

C) thunderstorms

D) soil type

23 / 35

Which one of the following has the largest population in a food chain?

A) Producers

B) Primary consumers

C) Secondary consumers

D) Decomposers

24 / 35

In the nitrogen cycle, it is accurate to describe the conversion of ammonium ions to nitrate ions as an oxidation because the nitrogen atom in the ammonium ion:

A) loses oxygen and gains hydrogen ions

B) loses oxygen and loses hydrogen ions

C) gains oxygen and gains hydrogen ions

D) gains oxygen and loses hydrogen ions

25 / 35

What is saprobiotic nutrition?

A) a method by which decomposers feed

B) a type of heterotrophic nutrition

C) a method of holozoic nutrition mode

D) all of the above

26 / 35

The main processes involved in cycling carbon through ecosystems are:

A) photosynthesis, feeding and ammonification, respiration, combustion

B) photosynthesis, feeding, respiration, combustion

C) photosynthesis, combustion feeding and ammonification

D) photosynthesis, feeding and assimilation, respiration, combustion

27 / 35

The process that fixes carbon atoms from an inorganic source (carbon dioxide) into organic compounds (for example, glucose) is called ____ ?

A) Fossilisation

B) Combustion

C) Photosynthesis

D) Assimilation

28 / 35

Carbon dioxide is removed from the atmosphere when

A) animals respire

B) plants respire

C) plants photosynthesise

D) Plants and animals respire

29 / 35

Which of the following is very important in the nitrogen cycle?

A) ammonification

B) extracellular digestion

C) enzymes digest

D) none of the above

30 / 35

What cycle does acid rain occur?

A) phosphorus cycle

B) sulphur cycle

C) water cycle

D) nitrogen cycle

31 / 35

Which of the following compound is caused by acid rain?

A) sulfur dioxide

B) nitrogen oxides

C) sulfur dioxide and nitrogen oxides

D) sulfur dioxide, nitrogen oxides and water

32 / 35

Which type of bacteria reduces nitrate to nitrogen gas that escapes from the soil?

A) Denitrifying bacteria

B) Nitrogen-fixing bacteria

C) De-nitrogen bacteria

D) redox bacteria

33 / 35

All successions share which of the following features?

A) Each stage changes the abiotic conditions.

B) The community becomes more complex as the succession progresses.

C) More ecological niches are created as the succession progresses.

D) All of the above

34 / 35

Decomposers _____ and ______ are key in returning nutrients to the ecosystem.

A) hytoplankton and Zooplankton

B) bacteria and fungi

C) benthos and fishes

D) carnivores and herbivores)

35 / 35

The micro-organisms that break down dead matter are:

A) herbivores

B) detritivores

C) decomposers

D) nitrogen-fixing bacteria

Your score is

The average score is 54%

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