Solutions to Q3
Complete

1. (c) Definitions:

(i) Microbe: A microbe, short for microorganism, is a microscopic organism such as bacteria, viruses, fungi, or protists that are too small to be seen with the naked eye. Microbes are diverse and can be found in various environments, including soil, water, air, and living organisms. They play essential roles in ecosystems, including decomposition, nutrient cycling, and disease causing.

(ii) Disease: Disease refers to a deviation from normal functioning or structure of an organism, resulting in physical or physiological abnormalities. It is typically caused by pathogens, such as bacteria, viruses, or parasites, that invade the body and disrupt normal bodily functions.

(iii) Toxin: A toxin is a harmful substance produced by living organisms, such as bacteria, fungi, or plants. Toxins can cause adverse effects when they enter the body. They can target specific tissues or organs, disrupt normal cellular functions, and lead to a range of symptoms or diseases.

(iv) Metabolic Waste: Metabolic waste refers to the byproducts generated during the metabolic processes of organisms. It includes substances such as carbon dioxide, water, urea, ammonia, and various other chemicals that are produced as a result of cellular metabolism.

1. (d) Adaptations of caterpillars to their habitat:

2. Camouflage: Many caterpillars have evolved color patterns and textures that allow them to blend in with their surroundings. This adaptation helps them avoid predators and increases their chances of survival.

3. Eating Specialized Diets: Caterpillars often have specific diets, feeding on particular plant species or even specific parts of plants. This adaptation enables them to utilize unique nutrient sources and reduces competition for food with other organisms in their habitat.

4. Defensive Mechanisms: Caterpillars possess various defense mechanisms to protect themselves from predators.Some caterpillars have spiky or bristly hairs that deter predators, while others produce toxic or irritating compounds that make them unpalatable or harmful to potential attackers.

Solutions to Q2

Question 2 (a)

1. It has a large surface area due to the presence of numerous finger-like projections called villi, which increase the absorption of nutrients.
2. The small intestine has specialized cells called enterocytes that line the walls and are responsible for absorbing nutrients into the bloodstream.
3. It has a highly folded inner lining, which further increases the surface area available for absorption.
4. The small intestine produces enzymes and secretes mucus to aid in the digestion and breakdown of food.

2b 1. Nitrogen
2 . Potassium
3. Phosphorus

1. C .

2. Water is crucial for photosynthesis, the process by which plants convert sunlight into energy. Water is one of the key ingredients needed for this process to occur.

3. Water helps transport nutrients and minerals from the soil to different parts of the plant. It acts as a carrier, allowing essential substances to reach the roots, stems, leaves, and other plant tissues.

4. Water plays a vital role in maintaining turgidity, which is the firmness and rigidity of plant cells. When plants have enough water, their cells become turgid, helping them stay upright and maintain their structure.

2 d. High concentrations of salts, such as in saline soils, can reduce transpiration in plants because it creates a water potential gradient that makes it harder for water to move from the plant's tissues to the surrounding environment. This reduces the rate of water loss through transpiration.

1. e . 1. Trypsin
2. Chymotrypsin
3. Carboxypeptidase

Solutions to Q1
Complete

c (I) 1. Marchantia
2. Pellia

C (ii) mosses

d. (i)
1. They have elongated bodies with numerous segments, each bearing a pair of legs.
2. They have a single pair of antennae and a pair of venomous claws called forcipules.
3. They are carnivorous, feeding primarily on insects and other small invertebrates.
4. They have a distinctively fast and agile movement, allowing them to capture prey and escape predators.

d. (ii). Four characteristics of Diplopoda are:

1. They have elongated bodies composed of numerous segments, with two pairs of legs per segment.
2. They have a rounded or cylindrical shape, and their bodies are often covered in a hard exoskeleton.
3. They are herbivorous or detritivorous, feeding primarily on decaying plant material.
4. They have a slower and more deliberate movement compared to centipedes, and they use their legs in a wave-like motion when walking.

d. Chilopoda: Centipedes
Diplopoda: Millipedes

e. (I) 1. Coleoprata
e (ii) 1. Vulgare

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d. (i)
1. They have elongated bodies with numerous segments, each bearing a pair of legs.
2. They have a single pair of antennae and a pair of venomous claws called forcipules.
3. They are carnivorous, feeding primarily on insects and other small invertebrates.
4. They have a distinctively fast and agile movement, allowing them to capture prey and escape predators.

c (I) 1. Marchantia
2. Pellia

5aii.
The observation that eukaryotic cells are generally larger than prokaryotic cells is because eukaryotic cells have a more complex structure and contain membrane-bound organelles, such as the nucleus, mitochondria, and endoplasmic reticulum. These organelles contribute to the larger size of eukaryotic cells compared to prokaryotic cells, which lack these membrane-bound structures.

Q5ai.

The observation that food chains are usually limited to three or four trophic levels means that in an ecosystem, there are typically three or four levels of organisms that transfer energy through feeding relationships. Each trophic level represents a different position in the food chain, starting with producers (plants), then primary consumers (herbivores), followed by secondary consumers (carnivores or omnivores), and sometimes tertiary consumers (top predators). This limitation occurs because energy is lost as it moves up the food chain, so there is not enough energy available to support a large number of trophic levels.

Question 3a,b solution 💯✅

(a) Bread becomes moldy when left at room temperature for days due to the presence of moisture and spores in the environment. Mold is a type of fungi that thrives in warm and humid conditions. When bread is exposed to these conditions, the moisture content inside the bread provides an ideal breeding ground for mold spores. Over time, the spores land on the bread's surface and start to grow, forming visible mold.

(b) There are several ways to prevent bread from developing molds:

1. Store it in a cool and dry place: Keeping bread in a cool and dry environment helps to minimize moisture, thus reducing the chances of mold growth. It is advisable to store bread in airtight containers or bags to maintain freshness and prevent exposure to dampness in the air.

2. Freeze it: If you want to preserve bread for an extended period, freezing is a great option. Freezing bread prevents mold growth by halting the activity of mold spores. It is essential to wrap the bread tightly in plastic wrap or foil to maintain its texture and prevent freezer burn. When ready for consumption, allow the bread to thaw at room temperature.

3. Use preservatives: Some commercial bread products contain preservatives to prolong shelf life and inhibit mold growth. These preservatives, such as calcium propionate or sorbic acid, help prevent mold development by creating an unfavorable environment for its growth. However, it is important to read product labels and be aware of any potential allergies or dietary restrictions.

By implementing these preventative measures, you can significantly reduce the risk of bread developing molds and prolong its

Question 3a,b

Solutions to Q1

1(i) Taxonomy: Taxonomy is the branch of biology that deals with the classification, identification, and naming of organisms. It involves organizing and categorizing living organisms based on their similarities and evolutionary relationships. Taxonomy helps in understanding the biodiversity on Earth and provides a systematic way to study and communicate about different species.

1(ii) Binomial nomenclature: Binomial nomenclature is a system of naming species in which each species is given a unique two-part scientific name. It was introduced by Carl Linnaeus and is widely used in biology. The binomial name consists of the genus name (first part) followed by the specific epithet (second part). This naming system helps scientists across the world to have a standardized and universally recognized way of referring to specific species.

1b(i) Hepaticae (Liverworts):
1. Nonvascular plants: Hepaticae are nonvascular plants, meaning they lack specialized tissues for conducting water and nutrients. They rely on direct absorption from their surroundings.
2. Gametophyte dominance: The gametophyte generation of Hepaticae dominates the life cycle. It is the most visible stage and is responsible for the plant's vegetative growth and reproduction.

1b(ii) Musci (Mosses):
1. Small size: Mosses are small plants with a low-growing habit. They usually grow in dense clumps or carpets and are less than a few inches in height.
2. Moisture-dependent: Mosses require a moist environment to thrive. They lack true roots but have rhizoids that aid in absorption of water. They are typically found in moist habitats like damp forests, wetlands, or along stream banks.
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