Olympiad Test: Fibres To Fabrics -1 - Class 7 MCQ

Answer:
Introduction: Cashmere is a luxurious and highly sought-after fibre known for its softness, warmth, and durability. It is obtained from specific animals, and in this case, it is obtained from a particular animal.
Explanation: Cashmere fibre is obtained from the undercoat of certain animals, where it is found in small quantities. Among the options provided, the animal from which Cashmere is obtained is:
- Goat: Cashmere is primarily obtained from the Cashmere or Kashmir goat, which is native to the Himalayan regions of Asia, including India, Nepal, and Tibet. These goats have a double-layered coat consisting of a coarse outer layer and a soft, downy undercoat. It is this undercoat that produces the highly prized Cashmere fibre.
Conclusion: In conclusion, the expensive and rare fibre called Cashmere is obtained from goats, specifically the Cashmere or Kashmir goat. These goats have a soft undercoat that is carefully combed or sheared to collect the Cashmere fibre, which is then processed and used to create luxurious and high-quality products.

Bolls
Bolls are the protective capsules or pods that contain the small fluffy fibres being referred to in the question. These fibres are commonly known as cotton fibres and are used to produce cotton fabric.
Therefore, the correct answer is B: Bolls.

Silk moths feed only on mulberry leaves, hence these silk moths are also called as mulberry silk moths.

To determine which of the given options is a synthetic fiber, we need to understand the nature of each material.
1. Mohair:
- Mohair is the fiber obtained from the Angora goat.
- It is a natural fiber and not a synthetic fiber.
- Therefore, mohair is not the correct answer.
2. Alpaca:
- Alpaca is the fiber obtained from the domesticated South American alpaca.
- It is a natural fiber and not a synthetic fiber.
- Therefore, alpaca is not the correct answer.
3. Vicuna:
- Vicuna is the fiber obtained from the South American vicuña.
- It is a natural fiber and not a synthetic fiber.
- Therefore, vicuna is not the correct answer.
4. Rayon:
- Rayon is a synthetic fiber made from cellulose, which is derived from wood pulp or cotton linter.
- It is a versatile fiber that can mimic the properties of natural fibers like silk, cotton, and wool.
- Rayon is widely used in the textile industry.
- Therefore, rayon is the correct answer.
Conclusion:
- Among the given options, rayon is the only synthetic fiber.
- Mohair, alpaca, and vicuna are all natural fibers.

The life cycle of a silkworm is as follows:
Eggs:
- The life cycle begins with the female silkworm moth laying eggs on the leaves of the mulberry tree.
- The eggs are tiny and yellow in color.
- They take about 10-14 days to hatch.
Larva:
- Once the eggs hatch, the larva or caterpillar stage begins.
- The larvae are tiny and black and they immediately start feeding on the mulberry leaves.
- They undergo several molts or shed their skin as they grow.
- During this stage, the larvae continue to eat and grow rapidly.
- The larva stage lasts for about 4-6 weeks.
Pupa:
- After the larva stage, the silkworm enters the pupa stage.
- The pupa stage is also known as the cocoon stage.
- The silkworm spins a silk cocoon around itself using a single silk thread.
- The silk thread is produced from the silk glands of the silkworm.
- Inside the cocoon, the silkworm undergoes metamorphosis and transforms into an adult moth.
- The pupa stage lasts for about 2-3 weeks.
Adult:
- Once the metamorphosis is complete, the adult silkworm moth emerges from the cocoon.
- The adult moth has wings and a white or yellowish color.
- The primary purpose of the adult moth is to reproduce.
- The adult moth does not eat and has a short lifespan of about 2-3 days.
- The female moth lays eggs and the life cycle of the silkworm starts again.
Conclusion:
The correct answer is A: eggs, larva, pupa, adult. This is the correct sequence of the life cycle of a silkworm.

The suitable temperature for eggs of silkworm to hatch is 22 - 27°C (Option B). Here is a detailed explanation:
Temperature Range:
- The temperature range for the hatching of silkworm eggs is crucial for their successful development.
- If the temperature is too low, the eggs may not hatch, while high temperatures can also negatively affect the hatching process.
- Therefore, it is important to provide a suitable temperature range to ensure successful hatching.
Option Analysis:
A: 20 - 27°C
- The lower limit of this range is suitable, but the upper limit is slightly higher than the recommended range.
- It is possible that some eggs may hatch at this temperature range, but it may not be optimal for the majority of eggs.
B: 22 - 27°C
- This range falls within the recommended temperature range for silkworm egg hatching.
- The lower limit of 22°C ensures proper development, while the upper limit of 27°C provides a suitable environment for hatching.
- This option is the most appropriate choice.
C: 25 - 30°C
- The lower limit of this range is higher than the recommended range, which may affect the hatching process.
- The upper limit of 30°C is also higher than the recommended range, which may lead to poor hatchability.
D: 25 - 31°C
- Similar to option C, this range exceeds the recommended temperature range for hatching.
- The higher temperatures may have a negative impact on the eggs' development and hatchability.
Therefore, based on the analysis, option B (22 - 27°C) is the most suitable temperature range for the hatching of silkworm eggs.

c) trap a lot of air

Hair traps air close to the skin, which acts as an insulator to help maintain body temperature. This helps animals stay warm in cold conditions. Additionally, hair can provide protection from the sun, dirt, and injuries.

Explanation:
Shearing is the process of removing the fleece (wool) from the skin of a sheep. Here's a detailed explanation of why shearing is the correct answer:
1. Shearing definition: Shearing refers to the process of cutting or removing the wool from the sheep's body using specialized shearing tools.
2. Purpose of shearing: Shearing is done to harvest the wool from the sheep for various purposes, including textile production, insulation, and other commercial uses.
3. Method of shearing: Shearing is typically performed by skilled shearers who use electric or manual shears to carefully remove the wool. The process must be done with precision and care to avoid injuring the sheep.
4. Timing of shearing: Shearing is usually done once a year, usually in spring or early summer, depending on the climate and the type of sheep. This ensures that the sheep remains comfortable during the warmer months.
5. Benefits of shearing: Shearing provides several benefits for both the sheep and the wool industry. It helps prevent overheating and discomfort for the sheep, improves their hygiene, and promotes healthy wool growth.
6. Alternative options: The other options mentioned in the question - refining, shaving, and none of these - are not accurate descriptions of the process of removing the fleece from sheep.
Therefore, the correct answer is shearing (option B) when it comes to the removal of fleece from sheep.

Answer:
The correct answer is option C: llama and alpaca.
Here is a detailed explanation:
- Llama and alpaca are two domesticated animals found in South America.
- Both llama and alpaca belong to the camelid family and are known for their wool production.
- Llama wool is coarser and more durable, while alpaca wool is softer and more luxurious.
- Llama and alpaca wool are highly valued for their warmth and insulation properties.
- They are commonly used in the production of various textiles and clothing items.
- South America, particularly the Andean region, has a long history of using llama and alpaca wool for their traditional garments.
- Llama and alpaca wool are also exported worldwide for commercial purposes.
- These animals are well adapted to the high-altitude climates and rugged terrains of the Andes Mountains.
- Their wool serves as a protective layer against the cold temperatures and harsh weather conditions.
- Llama and alpaca wool are considered sustainable and eco-friendly options as they are renewable and biodegradable.
- The wool from these animals is highly sought after for its softness, warmth, and hypoallergenic properties.
In conclusion, llama and alpaca are the correct animals that yield wool found in South America.

Rearing of Silk Worm:
The rearing of silk worms is known as sericulture.
Explanation:
Here is a detailed explanation of why the correct answer is option B, sericulture:
Silviculture:
- Silviculture refers to the cultivation and management of forests.
- It involves activities such as planting, caring for, and harvesting trees for various purposes, including timber production.
Apiculture:
- Apiculture is the practice of rearing and managing bees for the production of honey, beeswax, and other bee-related products.
- It involves the construction and maintenance of beehives and the care of bee colonies.
Horticulture:
- Horticulture is the science and art of cultivating plants for food, medicinal purposes, or ornamental use.
- It includes activities such as gardening, landscaping, and crop production.
Sericulture:
- Sericulture specifically refers to the rearing of silk worms for the production of silk.
- It involves the cultivation of mulberry trees, which serve as food for the silk worms, and the management of the silk worm life cycle.
- Sericulture also includes the processes of harvesting the silk cocoons, extracting silk threads, and spinning them into silk fabric.
Therefore, the correct answer to the question is option B: sericulture, as it specifically relates to the rearing of silk worms for silk production.

Answer:

Introduction:

The common type of wool found in Ladhak and Tibet is ______ wool. The correct answer is option A, Yak.

Explanation:

1. Yak wool:

• Yak wool is the most common type of wool found in Ladhak and Tibet.


• Yak wool is obtained from the long-haired domesticated yak, a bovine animal native to the Himalayan region.


• Yak wool is known for its warmth, softness, and durability.


• It is commonly used to make various products such as clothing, blankets, and rugs.

2. Sheep wool:

• While sheep wool is a common type of wool worldwide, it is not specifically mentioned as common in Ladhak and Tibet.

3. Goat wool:

• Goat wool, also known as cashmere or pashmina, is another type of wool found in the region.


• However, it is not as common as yak wool in Ladhak and Tibet.

4. Camel wool:

• Although camels are found in the region, camel wool is not commonly associated with Ladhak and Tibet.


• Camel wool is more commonly found in desert regions.

In conclusion, the most common type of wool found in Ladhak and Tibet is yak wool. It is known for its warmth, softness, and durability, and is used to make various products.

The answer is D: Silk worms
Silk clothes are prepared from the silk fibers produced by silk worms. Here is a detailed explanation of the process:
Silk Production Process:
1. Silk worms: Silk worms are the larvae of the silk moth, also known as Bombyx mori. These worms are specifically bred for silk production.
2. Silk cocoon: Silk worms produce silk fibers to create a protective cocoon around themselves. The cocoon is made of a single continuous thread of silk, which can be several hundred meters long.
3. Harvesting the cocoon: The silk cocoons are carefully harvested after the silkworms have completed their life cycle and transformed into moths. The cocoons are collected and sorted for further processing.
4. Sericulture: The process of extracting silk from the cocoon is called sericulture. It involves several steps:
- Boiling the cocoon: The cocoons are boiled in hot water to soften the sericin, a natural gum-like substance that holds the silk fibers together.

- Reeling the silk: After boiling, the softened cocoons are unwound to extract the silk fibers. This process is known as reeling. The fibers are carefully reeled onto a spindle to create a continuous thread.

- Silk spinning: The silk threads obtained from multiple cocoons are then spun together to create a thicker and stronger thread. This thread is then ready for further processing.
5. Weaving: The silk thread is woven into fabric using various weaving techniques. The fabric can be dyed or printed to add color and patterns.
6. Finishing: After weaving, the silk fabric undergoes various finishing processes, such as washing, stretching, and ironing, to enhance its appearance and texture.
7. Garment production: The finished silk fabric is then used to make various types of clothing and accessories, such as dresses, scarves, ties, and more.
Key points to remember:
- Silk clothes are made from silk fibers produced by silk worms.
- The silk production process involves breeding silk worms, harvesting cocoons, boiling the cocoons to soften the sericin, reeling the silk fibers, spinning the threads, weaving the fabric, and finishing the fabric.
- Silk garments are known for their smooth, luxurious feel and lustrous appearance.

Spider silk is famous for its amazing toughness, and until recently a tensile strength of 1.3 gigapascals (GPa) was enough to earn it the title of strongest natural material.

Silk fiber:
Silk is a natural protein fiber that is produced by the silk moth larvae to create cocoons. It is known for its strength, smoothness, and lustrous appearance. The composition of silk fiber includes:
1. Proteins:
Silk fiber is primarily composed of proteins. The main protein present in silk is called fibroin, which makes up around 75-90% of the fiber. Fibroin is a strong and flexible protein that gives silk its unique properties.
2. Lipids:
Silk also contains lipids, which are organic compounds that are insoluble in water. These lipids are found in the outer layers of the silk fiber and help to protect and lubricate the fiber.
3. Carbohydrates:
While silk fiber is mainly composed of proteins, small amounts of carbohydrates may also be present. These carbohydrates are typically found in the form of sugars and are present in the silk glands of the silk moth larvae.
4. Fats:
Fats, which are a type of lipid, may also be present in silk fiber. Fats are important for providing energy and insulation, and they may contribute to the overall composition of silk.
In conclusion, the correct answer is B: proteins. Silk fiber primarily consists of proteins, with small amounts of lipids, carbohydrates, and fats also present.

Scouring is done after shearing the skin with fur. In scouring, the skin with fur is washed thoroughly in tanks to remove grease, dust and dirt.