NABTEB 2026 Biology (Type B) Answers – May/June

This post contains the verified NABTEB 2026 Biology (Type B) answers for the May/June examination. Use these structured solutions to cross-check your work, understand how marks are awarded, and revise key Biology concepts effectively.

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PART I

QUESTION 1

(1a) Advantages of multicellularity

• It allows division of labour, where different cells, tissues, and organs perform specialized functions efficiently.
• It increases the efficiency and survival of organisms by enabling them to carry out complex life processes.

(1bi) Differences between colonial and filamentous organisms

Colonial Organisms	Filamentous Organisms
They consist of many similar cells living together in a colony.	They consist of cells arranged end-to-end forming threads or filaments.
Individual cells can often survive independently when separated.	Individual cells usually cannot survive independently when separated.

(1bii) Examples

• Colonial organism: Volvox
• Filamentous organism: Spirogyra

(1c) Diagram

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PART II

QUESTION 2

(2ai) Definition of pollination

Pollination is the transfer of pollen grains from the anther of a flower to the stigma of the same flower or another flower of the same species.

(2aii) Features of an insect-pollinated flower

• Large and brightly coloured petals
• Presence of scent and nectar
• Pollen grains are sticky and heavy
• Stigma is sticky and not feathery

(2bi) Functions of the flowering plant

• Produces food through photosynthesis
• Carries out reproduction through flowers
• Absorbs water and mineral salts from the soil
• Provides support and transport of materials within the plant

(2bii) Diagram

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QUESTION 3

(3ai) Characteristics of good soil for agriculture

• It contains adequate nutrients/mineral salts for plant growth.
• It has good water-holding capacity and good drainage.
• It contains plenty of humus (organic matter) and supports soil organisms.

(3aii) Methods of improving poor soil

• Application of manure or fertilizers
• Crop rotation (or bush fallowing)

(3b) Methods of vegetative propagation with examples

• Cutting – e.g. cassava, sugarcane, rose
• Layering – e.g. cocoa, bougainvillea, mango
• Grafting/Budding – e.g. citrus (orange), mango
• Use of underground stems (suckers/rhizomes/tubers) – e.g. banana (suckers), ginger (rhizome), yam (tuber)

(3c) Advantages and disadvantages of vegetative propagation

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PART III

QUESTION 4

(4a) Diagram

(4bi) Functions of the teeth

Teeth are used for biting, cutting, tearing, crushing and grinding food into smaller particles. This increases the surface area of food for the action of digestive enzymes and makes swallowing easier.

(4bii) Functions of the tongue

The tongue mixes food with saliva to form a bolus and helps in swallowing. It also contains taste buds which enable the animal to detect different tastes in food.

(4biii) Functions of saliva

Saliva moistens and lubricates food, making it easier to swallow. It also contains the enzyme salivary amylase (ptyalin) which begins the digestion of starch into simpler sugars.

(4biv) Functions of the stomach

The stomach stores and churns food, mixing it with gastric juice. It also secretes enzymes and hydrochloric acid for the digestion of proteins and destroys harmful microorganisms present in food.

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QUESTION 5

(5a) Sense organs and their functions

• Eye – for vision
• Ear – for hearing and balance
• Nose – for smell
• Tongue – for taste

(5bi) Myopia (short-sightedness)

The eye defect is called Myopia (short-sightedness). It is a condition in which a person can see nearby objects clearly but distant objects appear blurred. This defect occurs when the eyeball is too long or the eye lens is too powerful, causing light rays from distant objects to focus in front of the retina instead of directly on it.

(5bii) Diagram

(5ci) Function of the cerebrum

The cerebrum controls voluntary actions, thinking, memory, and reasoning.

(5cii) Function of the cerebellum

The cerebellum controls balance, posture, and coordination of body movements.

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PART IV

QUESTION 6

(6ai) Sex-linked genes

Sex-linked genes are genes located on the sex chromosomes (X or Y chromosomes) and whose inheritance is associated with sex. Traits controlled by such genes are called sex-linked traits.

(6aii) Dominance

Dominance is the ability of one allele of a gene to express itself in the presence of another contrasting allele, thereby masking the effect of the recessive allele.

(6aiii) Hybrid

A hybrid is an offspring produced by crossing two genetically different individuals or varieties of the same species.

(6bi) Variation

Variation is the occurrence of differences among individuals of the same species in terms of physical appearance, physiological processes, behavioral patterns, and genetic constitution.

(6bii) Examples of continuous and discontinuous variation

(6biii) Importance of variation

• It enables organisms to adapt to changes in the environment.
• It increases the chances of survival of a species.
• It provides the raw materials for evolution and natural selection.

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