New Curriculum Second Term Biology examination for SS 1

Class: SS 1
Term: Second Term
Subject: Biology
Time: 2 hours
Total Marks: 70

SECTION A: OBJECTIVES (40 Marks)
Instruction: Answer all 40 questions. Choose the most appropriate answer. Each question carries 1 mark.

1. Which result provides strongest evidence that light intensity affects plant distribution in a school compound?
   (a) One plant grows near a wall on a single day    (b) The investigator prefers the sunny site    (c) Repeated counts show a consistent difference across similarly sampled sunny and shaded plots    (d) The two sites have not been measured at all
2. Why does a food web usually represent feeding relationships better than one food chain?
   (a) every consumer has exactly one food source    (b) an organism may feed at several points in interconnected pathways    (c) energy is created at higher trophic levels    (d) all prey species are equally abundant
3. An onion cell loses water in concentrated salt solution. The ________ of its protoplast away from the wall is termed plasmolysis.
   (a) division    (b) shrinkage    (c) fusion    (d) expansion
4. An organelle is damaged and the cell releases less usable energy from nutrients. Identify the organelle.
   (a) nucleus    (b) cell wall    (c) mitochondrion    (d) large vacuole
5. A group counts twenty snails of one species in a school garden. Those snails constitute a ________.
   (a) biome    (b) community    (c) population    (d) biosphere
6. A field has a few damaged leaves but many ladybirds feeding on aphids. Which decision best reflects ecological pest control?
   (a) Assess infestation levels and protect natural predators before deciding on intervention    (b) Spray indiscriminately without identifying the pest    (c) Remove every plant with a minor leaf mark    (d) Release predators without checking whether they feed on the pest
7. ________ is the practice of placing viable seeds in prepared soil for crop establishment.
   (a) Culling    (b) Milking    (c) Weaning    (d) Sowing
8. A vegetable grower wants to minimise water loss and supply water near plant roots. Which irrigation method best fits this aim?
   (a) Flooding the whole field continuously    (b) Overhead sprinkling at midday    (c) Drip irrigation    (d) Uncontrolled surface runoff
9. Under which ecological circumstances could a pyramid of numbers be inverted?
   (a) a large population of grass plants supports fewer grazers    (b) solar energy reaches many grass blades    (c) numerous seeds support a few rodents    (d) one large tree supports many small insects
10. Organic manure improves soil chiefly through ____.
    (a) addition of organic matter and gradual nutrient release    (b) instant removal of all soil organisms    (c) permanent replacement of soil water    (d) conversion of every soil particle into sand
11. The main reason the nucleus is important in a dividing cell is that it ____.
    (a) replaces the plasma membrane during division    (b) directly manufactures the cell wall in all cells    (c) contains genetic material needed for controlled cell activities and division    (d) serves as the main site of aerobic respiration
12. An energy pyramid is narrow at higher trophic levels. What accounts for the decline?
    (a) consumers manufacture additional solar energy    (b) energy passes unchanged to every predator    (c) respiration and other life processes dissipate usable energy    (d) food chains always have the same number of organisms
13. A sprinkler system covers beds unevenly because some nozzles are blocked. The correct step is to ____.
    (a) inspect and clear the affected nozzles before repeating the distribution check    (b) increase flow indefinitely without examining the blockage    (c) ignore the dry strips and replace the crop variety    (d) stop all watering for the rest of the term
14. Which material is LEAST suitable for an ordinary school compost heap?
    (a) Vegetable peelings    (b) Dry leaves    (c) Grass clippings    (d) Plastic food wrappers
15. A student includes earthworms and soil pH in the same ecosystem study. The two belong respectively to ____.
    (a) biotic and abiotic components    (b) abiotic and biotic components    (c) two abiotic components    (d) two genetic components
16. Which crop-establishment decision is most likely to support uniform emergence?
    (a) Planting some seeds exposed and others deeply buried without reasons    (b) Planting viable seeds at comparable depth in a suitable seedbed    (c) Using seeds of unknown viability at random depths    (d) Allowing the seedbed to remain heavily compacted
17. Which organism occupies the second trophic level in grass → rat → snake → hawk?
    (a) Rat    (b) Grass    (c) Snake    (d) Hawk
18. ________ includes all Earth's regions in which living organisms occur.
    (a) A single population    (b) The lithosphere alone    (c) A local microhabitat    (d) The biosphere
19. Which approach is NOT a biological pest-control method?
    (a) Releasing a suitable parasitoid against a pest    (b) Conserving natural predators in the field    (c) Using predatory insects that feed on the target pest    (d) Applying a broad-spectrum synthetic insecticide as the sole control
20. A red blood cell swells in a highly dilute surrounding solution. Which process most directly explains the change?
    (a) solute diffusion out of an isotonic solution    (b) water entry by osmosis    (c) plasmolysis in a cellulose wall    (d) mitosis of a mature blood cell
21. In an investigation of osmosis using potato strips, the correct step before comparing final masses is to ____.
    (a) cut strips to different sizes without recording them    (b) leave different strips for unrelated durations    (c) change both solution concentration and temperature unpredictably    (d) blot each strip consistently and use its original mass as a reference
22. Which description most accurately distinguishes habitat from niche?
    (a) Habitat is where an organism lives; niche describes its role and resource use    (b) Habitat is its feeding level; niche is the Earth's rocky layer    (c) Habitat is its species name; niche is its chromosome number    (d) Habitat includes only non-living factors; niche includes only climate
23. Under a microscope, a cell is rectangular with a firm boundary and a large vacuole. What is the best initial identification?
    (a) Animal cell, because it has cytoplasm    (b) Bacterium, because every bacterium has a large vacuole    (c) Plant cell, supported by its wall and vacuole    (d) Virus, because it has an observable cell boundary
24. Which of these is NOT an edaphic factor?
    (a) Soil texture    (b) Soil water content    (c) Soil acidity    (d) Wind speed above the crop canopy
25. A properly managed compost heap should be turned periodically. The main reason is to ____.
    (a) prevent all microorganisms from acting    (b) improve aeration and support decomposition    (c) increase the proportion of non-degradable material    (d) eliminate the need for balanced moisture
26. In grass → grasshopper → frog → snake, most frogs disappear. Predict the initial change in grasshopper abundance.
    (a) increase grass by eliminating grasshoppers    (b) increase grasshopper numbers if other factors remain unchanged    (c) remove the grasshoppers' food source directly    (d) turn snakes into producers
27. A student is about to sow seeds in a prepared plot. Identify the correct preparatory step.
    (a) apply excess water until all air spaces disappear    (b) prepare a suitable seedbed and establish appropriate spacing    (c) scatter seed without considering depth or density    (d) remove the topsoil from the planting site
28. A farmer controls an insect pest by releasing its natural enemy. Classify this control method.
    (a) chemical control    (b) mechanical harvesting    (c) biological control    (d) crop irrigation
29. What is the strongest husbandry reason for feeding farm animals on a consistent schedule?
    (a) eliminate every possibility of disease    (b) remove the need to provide clean water    (c) support health, growth and reliable husbandry records    (d) guarantee equal feed conversion in all animals
30. The diagram represents energy transfer across trophic levels. If producers contain 10,000 kJ and transfer averages 10%, energy reaching the secondary consumer is ____.
    (a) 100 kJ    (b) 1,000 kJ    (c) 10 kJ    (d) 9,000 kJ
31. Which farm management activity is part of animal husbandry rather than irrigation?
    (a) Selecting breeding animals and managing their feeding    (b) Supplying water through drippers    (c) Constructing furrows for surface watering    (d) Adjusting the distribution of irrigation sprinklers
32. Soil moisture, sunlight and temperature measured in a quadrat are examples of ________ factors.
    (a) abiotic    (b) biotic    (c) genetic    (d) trophic
33. A forest contains birds, insects, fungi and shrubs interacting. Which grouping includes all these living populations?
    (a) One species population    (b) One abiotic factor    (c) One trophic level    (d) Biotic community
34. Which statement does NOT accurately describe energy flow in a food chain?
    (a) Energy enters most food chains through photosynthesis    (b) Energy cycles indefinitely from top predators back to producers    (c) Some energy leaves each trophic level as heat    (d) Only a fraction of consumed energy reaches the next level
35. A grower sows maize too densely and observes weak seedlings. Which explanation is best supported?
    (a) The plants have stopped all respiration    (b) Competition for light, water and nutrients has intensified    (c) The soil has necessarily become sterile overnight    (d) All seedlings have developed identical roots
36. All of the following are consumers in a grassland food web EXCEPT ____.
    (a) a grasshopper feeding on grass    (b) a lizard feeding on insects    (c) a hawk feeding on a lizard    (d) green grass using sunlight to make food
37. Which outcome does NOT normally follow mitosis in a body cell?
    (a) Production of two genetically similar daughter cells    (b) Preservation of chromosome number in daughter cells    (c) Growth and replacement of worn tissues    (d) Production of four haploid cells with different chromosome combinations
38. Before recommending pest treatment, the main reason to identify the pest correctly is to ____.
    (a) ensure every insect in the field is destroyed    (b) choose a control that targets the actual cause and avoids unnecessary harm    (c) avoid recording crop damage    (d) guarantee that weather cannot affect treatment
39. Which comparison between an onion epidermal cell and a human cheek cell is most defensible?
    (a) Both cells possess a cellulose wall of equal thickness    (b) Only the cheek cell contains cytoplasm    (c) The onion cell has a cellulose wall; the cheek cell lacks it    (d) The onion cell has no plasma membrane
40. A compost heap of dry leaves decomposes unusually slowly. Which practical change would improve decomposition?
    (a) mix in suitable moist green material and maintain aeration    (b) seal it permanently without allowing air exchange    (c) remove all moisture from the heap    (d) spread fresh plastic fragments through it

SECTION B: THEORY (30 Marks)
Instruction: Answer Question 1 and any other TWO questions. Each question carries 10 marks. Show your reasoning and use labelled diagrams where appropriate.

Question 1 (10 marks)
(a) Describe the main functions of the nucleus and mitochondria and explain how their roles differ. (4 marks)
(b) A learner places similar potato strips in water and concentrated salt solution. Predict the change in each, explain the water movement and state one important control variable. (6 marks)

Question 2 (10 marks)
(a) Distinguish population from community using a named school-garden example for each. (4 marks)
(b) Plan a simple comparison of two quadrats in sunny and shaded parts of a garden. Explain three controls or measurements needed for a meaningful comparison. (6 marks)

Question 3 (10 marks)
(a) Use the chain grass → grasshopper → frog → snake to identify the producer and primary consumer and give their trophic positions. (4 marks)
(b) A producer level holds 10,000 kJ and approximately 10% moves to each next level. Calculate the energy at the frog and snake, and explain why energy decreases up the chain. (6 marks)

Question 4 (10 marks)
(a) Compare the purposes of drip and sprinkler irrigation and identify two factors affecting the choice for a vegetable plot. (4 marks)
(b) Describe how composting and biological pest control could be combined in a school garden, indicating one precaution or monitoring step for each. (6 marks)

Objective Marking Scheme
Question 1 – ✅ (c) Repeated counts show a consistent difference across similarly sampled sunny and shaded plots
Question 2 – ✅ (b) an organism may feed at several points in interconnected pathways
Question 3 – ✅ (b) shrinkage
Question 4 – ✅ (c) mitochondrion
Question 5 – ✅ (c) population
Question 6 – ✅ (a) Assess infestation levels and protect natural predators before deciding on intervention
Question 7 – ✅ (d) Sowing
Question 8 – ✅ (c) Drip irrigation
Question 9 – ✅ (d) one large tree supports many small insects
Question 10 – ✅ (a) addition of organic matter and gradual nutrient release
Question 11 – ✅ (c) contains genetic material needed for controlled cell activities and division
Question 12 – ✅ (c) respiration and other life processes dissipate usable energy
Question 13 – ✅ (a) inspect and clear the affected nozzles before repeating the distribution check
Question 14 – ✅ (d) Plastic food wrappers
Question 15 – ✅ (a) biotic and abiotic components
Question 16 – ✅ (b) Planting viable seeds at comparable depth in a suitable seedbed
Question 17 – ✅ (a) Rat
Question 18 – ✅ (d) The biosphere
Question 19 – ✅ (d) Applying a broad-spectrum synthetic insecticide as the sole control
Question 20 – ✅ (b) water entry by osmosis
Question 21 – ✅ (d) blot each strip consistently and use its original mass as a reference
Question 22 – ✅ (a) Habitat is where an organism lives; niche describes its role and resource use
Question 23 – ✅ (c) Plant cell, supported by its wall and vacuole
Question 24 – ✅ (d) Wind speed above the crop canopy
Question 25 – ✅ (b) improve aeration and support decomposition
Question 26 – ✅ (b) increase grasshopper numbers if other factors remain unchanged
Question 27 – ✅ (b) prepare a suitable seedbed and establish appropriate spacing
Question 28 – ✅ (c) biological control
Question 29 – ✅ (c) support health, growth and reliable husbandry records
Question 30 – ✅ (a) 100 kJ
Question 31 – ✅ (a) Selecting breeding animals and managing their feeding
Question 32 – ✅ (a) abiotic
Question 33 – ✅ (d) Biotic community
Question 34 – ✅ (b) Energy cycles indefinitely from top predators back to producers
Question 35 – ✅ (b) Competition for light, water and nutrients has intensified
Question 36 – ✅ (d) green grass using sunlight to make food
Question 37 – ✅ (d) Production of four haploid cells with different chromosome combinations
Question 38 – ✅ (b) choose a control that targets the actual cause and avoids unnecessary harm
Question 39 – ✅ (c) The onion cell has a cellulose wall; the cheek cell lacks it
Question 40 – ✅ (a) mix in suitable moist green material and maintain aeration

Theory Marking Scheme

Question 1:
(a) Nucleus holds genetic information/controls cell activities (2); mitochondria carry out much aerobic energy release (2). (4 marks)
(b) Water strip gains water/turgidity (1); salt strip loses water/shrinks (1); movement through selectively permeable membranes from higher to lower water potential correctly explained (2); one valid control e.g. initial size, time, temperature (2). (6 marks)

Question 2:
(a) Population: organisms of one species, e.g. garden snails (2); community: interacting populations e.g. snails, grass, ants and fungi (2). (4 marks)
(b) Award 2 marks each for any three: same quadrat area/sampling method; replicate samples; record sunlight intensity or shade; record soil moisture/other abiotic variables; calculate comparable organism counts and note conditions. (6 marks)

Question 3:
(a) Grass producer level 1 (2); grasshopper primary consumer level 2 (2). (4 marks)
(b) Frog level 3 receives 100 kJ with method (2); snake level 4 receives 10 kJ with method (2); respiration/heat/metabolic use, waste and uneaten matter reduce transfer (2). (6 marks)

Question 4:
(a) Drip: controlled supply near roots (2); sprinklers: spray distributed over plot (2). (4 marks)
(b) Use suitable biodegradable material, moisture and turning to support composting (2); apply mature compost hygienically (1); identify target pest and appropriate natural enemy (2); monitor infestation/avoid harm to non-targets (1). (6 marks)
Accept scientifically correct equivalents. Award method marks for valid reasoning; do not award a mark twice for the same point.