**1. SPECIMEN A.**
*(Diagram of a tadpole/larval specimen with parts labeled 1–9)*
**(a)**
i. Suggest an appropriate title for Specimen **A**.
ii. Label the parts/structures numbered 1 – 9.
iii. Mention three (3) morphological adaptations of Specimen **A**.
iv. Give four modifications that occur in Specimen **A** to develop to adult stage.
v. Name two behaviours engaged by Specimen **A** in its habitat.
vi. What is the most predominant type of feeding of Specimen **A**.
vii. Name the taxonomic order of Specimen **A**.
**(b).** Observe Specimens **B** and **C**.
i. Name the taxonomic class, order, family and genus of Specimens **B** and **C**.
ii. Give four (4) characteristics of Specimen **B**.
iii. Make a labeled diagram of 7 - 9 cm of the lateral view of Specimen **B**.
iv. In a tabular form give two (2) morphological differences and similarities between Specimens **B** and **C**.
v. Outline four (4) factors that attract Specimen **B** to humans.
**2.** a) Make a labeled diagram of 7 - 9 cm of the lateral view of Specimen **C**
b) Give four (4) characteristics of Specimens **C**.
©IJMBE/ABU/2024
---
## 2024 IJMBE BIOLOGY III A contd.
| Test | Observation | Inference |
|------|-------------|-----------|
| Add 10 drops of water to Food substance followed by two drops of copper sulphate and then 10 drops of caustic soda | Violet colour observed | Protein present |
---
## IMAGE 1 (Continuation page)
*(Diagram of Specimen M — cross-section of a plant stem with parts labeled 1–10)*
**Specimen M** ___________________________
---
**-2-**
### 2024 IJMBE BIOLOGY III A contd.
**You are provided with Specimen D.**
c) Identify Specimen **D** without any reason.
d) Name the taxonomic phylum, class, order and family of Specimen **D**.
e) Name the structure for gaseous exchange in Specimen **D**.
f) Outline four (4) economic importance of Specimen **D**.
g) Using a sharp scalpel, cut open the lateral side from the anus to the operculum of Specimen **D** to show the alimentary canal system. Draw a labeled diagram of 7 - 8 cm of the alimentary canal system.
**3** Specimens F, G and H are inflorescences provided. Study them carefully and use them to answer the questions that follow:
a) i. State the type of inflorescence in each case
ii. What are the likely pollinating agents for F and G.
b) Specimen I is provided. Observe it carefully and answer the questions that follow:
i. Draw and label the entire specimen
ii. Classify the specimen to generic level
State one prominent feature of the specimen which enables it to survive in its environment
4a. specimens J, K and L are provided. Study them carefully and answer the questions that follow:
State the habitat for each specimen
State one feature that makes each specimen adapted to its habitat
b. specimen M is provided in your question paper. Use it to answer the questions which follow.
i. Identify the specimen
ii. Label the parts numbered 1 -10
Give two functions of the part labeled 9.
4b. A food specimen is provided in the laboratory in your school, on your experimental bench you are also provided with iodine solution, nitric acid, Fehling's solution, Sudan III solution and plain sheets of paper. How will you determine the presence of starch, glucose, protein and lipids in the food specimen? Tabulate your answer in the format below:
# 2024 IJMBE Biology III A — Full Solutions
## QUESTION 1 — SPECIMEN A (Tadpole)
### (a)
**i. Appropriate Title:**
Tadpole larva of a frog (*Rana* sp.) — lateral view
**ii. Labels (1–9):**
1. Eye
2. Nostril
3. Mouth
4. Dorsal fin
5. Tail fin
6. Gill cover (operculum)
7. Forelimb bud
8. Hindlimb bud
9. Cloaca / Vent
**iii. Three Morphological Adaptations:**
1. Streamlined body — for easy movement through water
2. Flattened tail — acts as a paddle for swimming
3. Gills (external/internal) — for gaseous exchange in water
**iv. Four Modifications (Metamorphosis to Adult):**
1. Tail is gradually absorbed (reabsorbed by histolysis)
2. Gills disappear and lungs develop for air breathing
3. Forelimbs and hindlimbs develop
4. Mouth widens and digestive system changes from herbivorous to carnivorous type
**v. Two Behaviours in Habitat:**
1. Schooling behaviour — tadpoles swim in groups for protection
2. Feeding behaviour — they graze on algae and aquatic vegetation
**vi. Most Predominant Type of Feeding:**
Herbivorous (filter feeding on algae and plant matter)
**vii. Taxonomic Order:**
Order — **Anura** (Salientia)
---
### (b) Specimens B and C *(likely Toad and Frog)*
**i. Taxonomic Classification:**
| Rank | Specimen B (Toad) | Specimen C (Frog) |
|------|-------------------|-------------------|
| Class | Amphibia | Amphibia |
| Order | Anura | Anura |
| Family | Bufonidae | Ranidae |
| Genus | *Bufo* | *Rana* |
**ii. Four Characteristics of Specimen B (Toad):**
1. Skin is dry, rough and warty
2. Has parotoid glands behind the eyes that secrete toxic substances
3. Shorter hind limbs — adapted for walking/hopping rather than leaping
4. Tympanic membrane (eardrum) is visible behind the eye
**iii. Labeled diagram of lateral view of Specimen B:**
*(Draw a 7–9 cm diagram of a toad showing: eye, tympanic membrane, parotoid gland, nostril, mouth, forelimb, hindlimb, warty skin, cloaca)*
**iv. Morphological Differences and Similarities:**
| Feature | Specimen B (Toad) | Specimen C (Frog) |
|---------|-------------------|-------------------|
| **Differences** | | |
| Skin texture | Dry and warty | Smooth and moist |
| Hind limbs | Short | Long and powerful |
| **Similarities** | | |
| Body plan | Four limbs present | Four limbs present |
| Eyes | Prominent, bulging eyes | Prominent, bulging eyes |
**v. Four Factors that Attract Specimen B (Toad) to Humans:**
1. Presence of insects and pests (food source) near human dwellings
2. Availability of moisture/water around homes
3. Artificial lighting attracts insects which in turn attract toads
4. Warm sheltered environments provided by human structures
---
## QUESTION 2 — SPECIMEN C (Frog)
**a) Labeled Lateral Diagram of Specimen C (Frog):**
*(Draw a 7–9 cm lateral view showing: nostril, eye, tympanic membrane, mouth, forelimb, hindlimb with webbed feet, smooth skin, cloaca, dorsal surface)*
**b) Four Characteristics of Specimen C (Frog):**
1. Skin is smooth, moist and thin — used for cutaneous respiration
2. Long, powerful hind limbs with webbed feet for jumping and swimming
3. Protrusible, sticky tongue for capturing prey
4. Ectothermic (cold-blooded) — body temperature depends on the environment
---
## Food Test Table (from bottom of Image 2)
| Test | Observation | Inference |
|------|-------------|-----------|
| Add 10 drops of water + 2 drops copper sulphate + 10 drops caustic soda | Violet/purple colour | Protein present |
---
## SPECIMEN D (Fish — likely *Tilapia* sp.)
**c) Identity:**
Tilapia (*Tilapia* sp.) / Catfish — a bony fish
**d) Taxonomic Classification:**
| Rank | Name |
|------|------|
| Phylum | Chordata |
| Class | Osteichthyes (Actinopterygii) |
| Order | Perciformes |
| Family | Cichlidae |
**e) Structure for Gaseous Exchange:**
**Gills** (covered by the operculum)
**f) Four Economic Importance:**
1. Source of protein/food for humans
2. Source of income/livelihood for fishermen
3. Used in scientific research and laboratory studies
4. Contributes to aquaculture and fish farming industry
**g) Alimentary Canal Diagram:**
*(Draw and label 7–8 cm showing: mouth → buccal cavity → oesophagus → stomach → intestine → rectum → anus)*
---
## QUESTION 3 — Inflorescences (F, G, H) and Specimen I
### (a) i. Types of Inflorescence:
| Specimen | Type of Inflorescence |
|----------|-----------------------|
| F | Spike (e.g., maize) |
| G | Raceme (e.g., Delonix) |
| H | Capitulum/Head (e.g., sunflower) |
### ii. Likely Pollinating Agents for F and G:
- **F (Spike/Maize):** Wind (anemophily)
- **G (Raceme):** Insects (entomophily) — bees, butterflies
---
### (b) Specimen I *(likely a xerophyte, e.g., cactus)*
**i.** Draw and label the entire specimen showing: spine/modified leaves, succulent stem, waxy cuticle, areoles
**ii. Classification to Generic Level:**
- Kingdom: Plantae
- Division: Angiospermophyta
- Class: Dicotyledonae
- Order: Caryophyllales
- Family: Cactaceae
- Genus: *Opuntia*
**One Prominent Feature for Survival:**
Succulent (fleshy) stem that stores water, enabling survival in dry/desert environments
---
## QUESTION 4a — Specimens J, K, L
| Feature | Specimen J (Aquatic) | Specimen K (Terrestrial/Desert) | Specimen L (Arboreal/Forest) |
|---------|---------------------|-------------------------------|------------------------------|
| Habitat | Fresh water / pond | Dry land / desert | Trees / tropical forest |
| Adaptation | Streamlined body / gills / fins | Thick cuticle / deep roots / water storage | Climbing structures / camouflage |
---
## Specimen M (Plant Stem T.S. — likely Dicot stem)
**b) i. Identity of Specimen M:**
Transverse Section (T.S.) of a **Dicotyledonous stem** (e.g., *Helianthus* — sunflower stem)
**ii. Labels 1–10:**
| Number | Structure |
|--------|-----------|
| 1 | Cuticle |
| 2 | Epidermis |
| 3 | Cortex |
| 4 | Endodermis |
| 5 | Phloem |
| 6 | Cambium |
| 7 | Xylem |
| 8 | Pith |
| 9 | Vascular bundle |
| 10 | Pericycle |
**Two Functions of Part Labeled 9 (Vascular Bundle):**
1. **Transport of water and mineral salts** upward from roots via the xylem
2. **Transport of manufactured food (sucrose)** from leaves to other parts of the plant via the phloem
---
## QUESTION 4b — Food Tests Table
| Food Substance | Reagent Used | Procedure | Observation | Inference |
|---------------|-------------|-----------|-------------|-----------|
| Starch | Iodine solution | Add a few drops of iodine to food sample | Blue-black colouration | Starch present |
| Glucose | Fehling's solution | Add Fehling's A & B, heat in water bath | Brick-red precipitate | Glucose present |
| Protein | Nitric acid (Xanthoproteic) / Biuret | Add caustic soda + copper sulphate (Biuret test) | Violet/purple colour | Protein present |
| Lipid | Sudan III solution / Plain paper | Apply food to paper OR add Sudan III solution | Red staining (Sudan III) / Translucent grease spot on paper | Lipid present |