1. The branch of Biology that deals with the principles of classification of organisms is known as

A. biological index
B. nomenclature
C. taxonomy ✔

D. ecology

Explanation:
Taxonomy is the branch of Biology concerned with the classification of organisms.

2. Which of the following structures is a tissue?

A. Vessel element
B. Blood ✔

C. Sieve tube element
D. Erythrocyte

Explanation:
Blood is a connective tissue made up of cells suspended in plasma.

3. Which of the following cells are not regarded as specialized?

A. Sperm cells
B. Root tip cells ✔

C. Muscle cells
D. Somatic cells

Explanation:
Root tip cells are meristematic and not specialized.

4. Which of the following pairs of cells carry out the same function?

A. Cheek cell and red blood cell
B. Spermatozoan and ovum ✔

C. Palisade cell and epidermal cell
D. Root tip cell and guard cell

Explanation:
Both spermatozoan and ovum are gametes involved in reproduction.

5. If Amoeba is placed in a salt solution, the contractile vacuoles would

A. be bursting more frequently
B. be more numerous
C. be formed less frequently ✔

D. grow bigger before they burst

Explanation:
In a hypertonic (salt) solution, less water enters the Amoeba.

6. In which of the following habitats is Paramecium not found?

A. Pond
B. Aquarium
C. Lake
D. Puddle ✔

Explanation:
Paramecium is commonly found in permanent freshwater habitats, not temporary puddles.

7. The following processes are involved in water movement in the endodermis except

A. osmosis
B. vacuolar pathway
C. diffusion ✔

D. active transport

Explanation:
Water movement in the endodermis does not occur by diffusion.

8. Cells that utilize a lot of energy are characterized by the presence of a large number of

A. vacuoles
B. mitochondria ✔

C. endoplasmic reticulum
D. ribosomes

Explanation:
Mitochondria release energy needed for cellular activities.

9. The part labelled II in the diagram is

A. centriole
B. chloroplast ✔

C. chromatid
D. tonoplast

Explanation:
The labelled structure represents a chloroplast involved in photosynthesis.

10. The part labelled I is called the

A. nucleolus
B. centromere ✔

C. centriole
D. spindle

Explanation:
The centromere joins the two chromatids of a chromosome.

11. Secondary growth is brought about by the activities of the

A. phellogen and phelloderm
B. phellogen and procambium
C. vascular cambium and phelloderm
D. vascular cambium and phellogen ✔

Explanation:
Secondary growth is caused by vascular cambium and cork cambium (phellogen).

12. A monocot root is different from a dicot root by having

A. endodermis
B. cambium
C. wide pith ✔

D. root hair

Explanation:
Monocot roots possess a large central pith.

13. Which of the following statements best describes haemoglobin? It is

A. yellowish in colour
B. a red blood cell
C. an oxygen-carrying pigment ✔

D. needed for blood clotting

Explanation:
Haemoglobin is the pigment that transports oxygen in the blood.

14. Inhaled air is made warm and moist in the

A. epiglottis
B. nasal cavity ✔

C. trachea
D. mouth

Explanation:
The nasal cavity warms, moistens, and filters inhaled air.

15. Which of the following structures is not involved in respiration?

A. Lung books
B. Mouth
C. Stomach ✔

D. Trachea

Explanation:
The stomach is involved in digestion, not respiration.

16. Filtrate in the Bowman's capsule contains vitamins because

A. only a small amount is required by the body
B. they can be reabsorbed into the blood
C. they have low molecular weight ✔

D. most of them are fat-soluble

Explanation:
Vitamins are small molecules and pass through the glomerulus.

17. More sweat is produced during muscular exercise because

A. the contracting muscles produce water
B. fermentation occurs in muscles
C. the temperature of the body rises ✔

D. the muscle fatigues

Explanation:
Sweating helps to regulate increased body temperature.

18. Which of the following neurons may not have a myelin sheath?

A. Effector cells
B. Intermediate neurons ✔

C. Motor neurons
D. Sensory neurons

Explanation:
Some intermediate (relay) neurons lack a myelin sheath.

19. Which of the following is an effector organ?

A. Tongue ✔

B. Skin
C. Nose bridge
D. Ear glands

Explanation:
The tongue contains muscles that act as effectors.

20. During sexual reproduction in Paramecium, how many times does the zygote divide to produce eight nuclei?

A. 1
B. 2
C. 3 ✔

D. 4

Explanation:
$2^3 = 8$, so three divisions are required.

21. The testes in male mammals descend into the scrotal sac because

A. there is congestion in the lower abdomen
B. they run the risk of being destroyed
C. they need special support
D. they require a relatively low temperature ✔

Explanation:
Sperm production requires a temperature lower than body temperature.

22. Some animals return to water bodies to reproduce because

A. natural enemies destroy their eggs on land
B. water nourishes their embryos and their young ones ✔

C. they are close to their ancestors and imitate them
D. the temperature on land is not suitable for development

Explanation:
Water provides a suitable environment for embryo development.

23. Which of the following methods is appropriate for the cultivation of cassava?

A. Budding
B. Fragmentation
C. Root cutting
D. Stem cutting ✔

Explanation:
Cassava is propagated using stem cuttings.

24. What will be the chromosome number of the hybrid of two varieties of a plant with $36$ chromosomes in the endosperm cell?

A. 12
B. 24 ✔

C. 36
D. 48

Explanation:
Endosperm is $3n$, so $n = 12$ and the diploid number is $2n = 24$.

25. Kreb’s cycle occurs in the

A. mitochondria ✔

B. cytoplasm
C. nucleus
D. ribosomes

Explanation:
Krebs cycle takes place in the mitochondrial matrix.

26. The process whereby electrons are emitted from chlorophyll and returned to it unchanged is known as

A. non-cyclic phosphorylation
B. photochemical reaction
C. photophosphorylation
D. cyclic photophosphorylation ✔

Explanation:
In cyclic photophosphorylation, electrons return to chlorophyll.

27. Which of the following statements about photosynthesis is not true?

A. Plants can photosynthesize without an increase in dry weight ✔

B. Carbon dioxide is absorbed by the leaves in bright light
C. Oxygen is produced from the breakdown of water
D. Photosynthesis occurs in green plants

Explanation:
Photosynthesis results in an increase in dry mass.

28. The removal of all the phloem tissues of the stem of a plant close to the root system for a long period of time is likely to

A. provide more energy to the roots
B. accumulate more starch in the roots
C. cause the underground roots to develop buds
D. cause the plant to wither and die ✔

Explanation:
Food cannot be transported to the roots, leading to death.

29. Which of the following groups of substances are not six-carbon compounds?

A. Glucose and lactose
B. Lactose and cellulose
C. Glucose, lactose, and pyruvate
D. Pyruvate and cellulose ✔

Explanation:
Pyruvate has $3$ carbons and cellulose is a polymer.

30. The conversion of glucose to starch in the leaf during the day principally

A. enables photosynthesis
B. prevents osmotic problems ✔

C. enables the leaf to store the starch
D. enables glucose to be used up

Explanation:
Starch is insoluble and prevents osmotic imbalance.

31. A purple colour was obtained when sodium hydroxide solution and a drop of copper sulfate solution were added to a food substance. The food substance is likely to be a

A. carbohydrate
B. fat
C. protein ✔

D. sugar

Explanation:
This is a positive Biuret test for proteins.

32. Which of the following enzymes is active in the duodenum?

A. Pepsin
B. Renin
C. Trypsin ✔

D. Amylase

Explanation:
Trypsin acts in the duodenum to digest proteins.

33. The following organisms are producers except

A. Hibiscus
B. Mushroom ✔

C. Cactus
D. Spirogyra

Explanation:
Mushroom is a saprophytic fungus and not a producer.

34. Which of the following structures produces the greatest variety of digestive enzymes?

A. Salivary glands
B. Pancreas ✔

C. Stomach
D. Colon

Explanation:
The pancreas produces many digestive enzymes.

35. The following are abiotic components of an ecosystem except

A. temperature
B. oxygen
C. bacteria ✔

D. soil

Explanation:
Bacteria are living (biotic) components.

36. Use the information on the capture-recapture method to calculate the total number of organisms in a habitat.

First capture $= 200$
Second capture $= 120$
Marked in second capture $= 40$

A. 200
B. 360
C. 600 ✔

D. 800

Explanation:
Total population $= \dfrac{200 \times 120}{40} = 600$.

37. Ecological investigation in a habitat includes the following procedures except

A. choosing a habitat
B. identification of specimens
C. determining the genetic makeup of specimens ✔

D. measuring abiotic and biotic factors

Explanation:
Genetic analysis is not a routine ecological field procedure.

38. Which of the following substances when lost from the body of a mammal will not be returned to the ecosystem?

A. Sweat
B. Urea
C. Heat energy ✔

D. Carbon dioxide

Explanation:
Heat energy is dissipated and not recycled.

39. The rate of decomposition of organisms is faster in the tropical rainforest than in other biomes because

A. of the relatively constant daylight
B. there are more plants per square foot
C. of abundance of water ✔

D. of constant cool temperature

Explanation:
Warm and wet conditions favour decomposers.

40. A xerophyte conserves water by possession of the following features except

A. thick cuticle
B. sunken stomata
C. broad leaves ✔

D. fleshy stem

Explanation:
Broad leaves increase water loss and are not xerophytic features.