OAVS TGT Science Mock Test - 2 - OTET MCQ

Mucus is a viscous secretion that protects the inner lining of the stomach from the action of HCl.

Explanation:
The practice of clearing vast tracts of forests and cultivating a single species of plant promotes monoculture in the area. Here's a detailed explanation:
1. Monoculture:
- Monoculture refers to the cultivation of a single type of plant over a large area.
- In this practice, forests are cleared, and only one species of plant is cultivated.
- This results in a lack of biodiversity and a dominance of a single plant species in the area.
2. Lack of Biodiversity:
- Biodiversity refers to the variety of plant and animal species present in an ecosystem.
- Clearing forests and replacing them with a single species of plant reduces the overall biodiversity in the area.
- This is because other plant and animal species that were dependent on the natural forest habitat may not be able to survive in the monoculture environment.
3. Negative Impact on Ecosystem:
- Monoculture disrupts the natural balance of the ecosystem.
- It can lead to the loss of habitat for many native species, as they are unable to adapt to the monoculture environment.
- The absence of different plant species also affects the availability of food and resources for animals, further impacting the ecosystem.
4. Environmental Risks:
- Monoculture can increase the vulnerability of crops to pests, diseases, and climate change.
- With a lack of biodiversity, there is a higher risk of pests and diseases spreading rapidly and causing significant damage to the cultivated plant species.
- Climate change can also have a more severe impact on monocultures, as they lack the resilience provided by diverse plant species.
In conclusion, the practice of clearing forests and cultivating a single species of plant promotes monoculture in the area, which has negative implications for biodiversity, the ecosystem, and environmental resilience.

Red colour has longer wavelength so least scattered by smoke or fog.

The pair of kidney-shaped cells present around stomata are called guard cells.
Explanation:
- The stomata are small openings present on the surface of leaves and stems that allow for gas exchange.
- The guard cells are specialized cells that surround each stoma and control its opening and closing.
- The shape of the guard cells is kidney-shaped, with a bulge on one side and a concave on the other side.
- The inner side of the guard cells facing the stomatal pore is thicker and more rigid, while the outer side is thinner and flexible.
- When the guard cells take up water, they become turgid and swell, causing the stomatal pore to open.
- Conversely, when the guard cells lose water, they become flaccid and shrink, leading to the closure of the stomatal pore.
- The opening and closing of stomata by the guard cells regulate the exchange of gases, including carbon dioxide and oxygen, as well as the loss of water through transpiration.
- Guard cells also play a role in controlling the entry of pathogens and regulating the plant's response to environmental factors such as light, temperature, and humidity.

The build-up of lactic acid in our muscles while running (less oxygen conditions) causes cramps.

In all of them asexual reproduction takes place e.g., in spirogyra fragmentation, malarial parasite multiple fission and in yeast by budding.

Mariculture is a specialized branch of aquaculture involving the cultivation of marine organisms for food and other products in the open ocean, an enclosed section of the ocean, or in tanks, ponds or raceways which are filled with seawater.

Leishmania reproduces by binary fission.

Mitochondria are the organelles involved in the process of aerobic respiration. These membrane-bound organelles are often referred to as the powerhouse of the cell because they are responsible for producing ATP, the energy currency of the cell, through the process of aerobic respiration. Within the mitochondria, various stages of aerobic respiration, including the Krebs cycle and the electron transport system, take place to generate ATP efficiently.

Amrita Devi Bishnoi sacrificed her life for the protection of Khejri trees.
Amrita Devi Bishnoi was a brave environmentalist who gave her life to protect the Khejri trees in the 18th century. The incident took place in the Bishnoi community, which holds deep reverence for nature and wildlife.
Background:
- Amrita Devi Bishnoi belonged to the Bishnoi community, which is known for its strong belief in environmental conservation.
- The Bishnois follow the teachings of their founder, Guru Jambheshwar, who preached the importance of nature preservation.
The Sacrifice:
- In 1730, the then ruler of the region ordered the cutting of Khejri trees to build a new palace.
- Amrita Devi Bishnoi, along with her three daughters, refused to let the trees be cut down.
- She hugged one of the Khejri trees and proclaimed that she would sacrifice her life to protect them.
- The other villagers, inspired by her courage, also joined in and stood against the tree cutters.
The Aftermath:
- The tree cutters brutally killed Amrita Devi Bishnoi and her daughters.
- However, their sacrifice caught the attention of the authorities and the incident led to public outrage.
- The ruler was forced to revoke the order to cut down the Khejri trees, and the Bishnoi community's dedication to environmental conservation became widely recognized.
Legacy:
- The sacrifice of Amrita Devi Bishnoi and her daughters is celebrated as an act of bravery and devotion to nature.
- The incident played a significant role in raising awareness about the importance of tree conservation and inspired others to protect the environment.
- The Bishnoi community continues to promote environmental sustainability and is actively involved in tree plantation drives and wildlife conservation efforts.
Therefore, it is clear that Amrita Devi Bishnoi sacrificed her life for the protection of Khejri trees, making her a symbol of environmental activism and courage.

Butane is a saturated hydrocarbon. But + ane = Butane.

According to kinetic theory og the gas molecule are in a state of constant rapid motion in all possible direction colloiding in a radom manner with one another and with the wall of the container and b/w two successive collisions molecules travel in a straight line path but show haphozard motion due to collisions. 

To correct a myopic (nearsighted) person's vision, a concave lens is required. Here's a detailed explanation:
Definition:
- Myopia is a refractive error in which distant objects appear blurred, while close objects can be seen clearly.
- The far point is the point at which parallel rays of light entering the eye converge to form a focused image on the retina without any additional accommodation by the eye.
Explanation:
- In a myopic person, the far point of vision is closer than the normal distance of infinity.
- In this case, the far point is given as 80 cm in front of the eye.
- To correct the problem and bring the far point back to infinity, a lens is used.
Types of lenses:
- Convex lenses are thicker in the middle and thinner at the edges. They converge light rays and are used to correct hyperopia (farsightedness).
- Concave lenses are thinner in the middle and thicker at the edges. They diverge light rays and are used to correct myopia (nearsightedness).
Correct answer:
- In this case, to correct the myopic person's vision with a far point of 80 cm, a concave lens is required. Therefore, the correct answer is option A: Concave.

Urea is the primary nitrogenous waste removed by the kidneys.

Brass is a homogenous mixture of 70% of Copper and 30% Zinc by mass. Copper and Zinc forms homogenous mixture as constituent particles are not visible

The most abundant element in earth’s crust is Oxygen. It is present in earth crust in form of oxide, carbonate etc. of metal.

Cartilage is not found in the kidney. It is a connective tissue that provides support and flexibility and is found in various parts of the body, including the nose, ear, and larynx.

- Statement A: Potassium permanganate is actually purple in color, not orange. It is a powerful oxidizing agent commonly used in chemistry experiments.
- Statement B: Gases have maximum fluidity and least rigidity compared to liquids and solids. This is due to the fact that gas particles are far apart and move freely in all directions.
- Statement C: Solids do have a significant kinetic energy of particles, although it is less than that of liquids and gases. The particles in solids vibrate in fixed positions, contributing to their overall kinetic energy.
- Statement D: Inter-particle attraction does depend on the physical state of matter. In solids, the particles are closely packed together, leading to strong intermolecular forces. In liquids, the particles are more spread out, resulting in weaker forces. In gases, the particles are far apart and have very weak intermolecular forces.

The correct answer is Clostridium.
Key Points

• Anaerobic bacteria which help in nonsymbiotic nitrogen fixation is Clostridium pasteurianum.
• The conversion of atmospheric nitrogen into nitrates so that it can be utilized by plants is termed nitrogen fixation.
• The ability of nitrogen fixation is possessed only by certain prokaryotes containing an enzyme complex called dinitrogenase that catalyzes the reduction of dinitrogen to ammonia. eg: Rhizobium, Azotobacter, Clostridium, Beijerinckia, etc.
• There are two types of biotic or biological nitrogen fixation-
• non-symbiotic nitrogen fixation
• symbiotic nitrogen fixation
• Non-symbiotic nitrogen fixation
• It is the fixation of atmospheric nitrogen by the bacteria that are free-living in the soil.
• One of the non-symbiotic anaerobic bacteria that fixes nitrogen is Clostridium pasteurianum.
• Azotobacter chroococcum is another aerobic, free-living bacteria that fix atmospheric nitrogen.
• Azotobacter and Beijerinckia are the two major bacterial species engaged in nitrogen fixation in tropical climate regions, which supply nutrients for the growth of numerous crops.
• Symbiotic nitrogen fixation
• It is part of a mutualistic relationship in which plants provide a niche and fixed carbon to bacteria in exchange for fixed nitrogen.

Additional Information

•  Clostridium pasteurianum
• It is a producer of carboxylic acids.
• It is a mesophile.
• It was the first free-living (non-symbiotic) microorganism discovered that could fix free nitrogen from the air.
• Azotobacter
• It is a non-symbiotic nitrogen-fixing bacteria.
• These are gram-negative, aerobic, free-living that play an important role in the nitrogen cycle

 

1 u (atomic mass unit) or 1 amu is defined as 1/12th of the mass of a carbon-12 atom.

To prevent floods, afforestation is a crucial measure that can be taken. Afforestation refers to the process of establishing a forest, or stand of trees, in an area where there was no forest. Here's a detailed explanation of how afforestation helps in flood prevention:
1. Absorption of rainwater:
- Trees have deep roots that can absorb a significant amount of rainwater, preventing it from accumulating on the surface.
- The roots also help in maintaining the stability of the soil, reducing erosion and allowing the soil to retain more water.
2. Increased infiltration:
- Forests act as natural sponges, allowing rainwater to infiltrate into the ground.
- This infiltration process helps in recharging groundwater and maintaining consistent water levels, reducing the chances of flooding.
3. Regulation of water flow:
- Tree canopies slow down the rainfall, allowing it to fall gently and reducing the impact on the ground.
- The vegetation on the forest floor and the trunks of the trees slow down the movement of water, preventing it from rushing down and causing floods downstream.
4. Prevention of soil erosion:
- Forests help in holding the soil together with their roots, preventing erosion.
- Erosion can lead to the deposition of sediment in rivers and streams, which can block the flow of water and increase the risk of floods.
5. Creation of natural barriers:
- Forests can act as natural barriers, preventing the rapid movement of water during heavy rainfall.
- The dense vegetation can absorb and slow down the flow of water, reducing the chances of flooding in downstream areas.
Therefore, afforestation plays a vital role in flood prevention by improving water absorption, regulating water flow, reducing soil erosion, and creating natural barriers. By implementing afforestation measures, we can mitigate the risks associated with floods and protect both human settlements and the environment.

The fluid-filled balloon inside the cranium acts as a shock absorber for the brain, absorbing impact forces and reducing the risk of damage to the brain tissue during sudden movements or external impacts. This protective mechanism helps safeguard the brain from injuries that could impair its vital functions.

The term tissue was given by marie francois xavier bichat in the year 1792. he was a french anatomist and pathologist and he was also know as 'father of histology '

Observation of Sky Color from the Moon Surface:
The observed color of the sky as seen from the Moon surface is black. Here's a detailed explanation:
1. Absence of Atmosphere:
- The Moon does not have an atmosphere like Earth.
- Earth's atmosphere scatters sunlight, which results in the blue color of the sky as seen from the surface.
- Since the Moon lacks an atmosphere, there is no scattering of sunlight, and hence the sky appears black.
2. Direct View of Space:
- Without an atmosphere to scatter sunlight, the Moon's surface provides a direct view of space.
- When an astronaut stands on the Moon, they can see the vast expanse of space filled with stars, planets, and the Sun.
- The absence of scattering and atmospheric interference allows for a clearer view of celestial objects.
3. Contrast with Lunar Surface:
- The black color of the sky provides a stark contrast with the grayish color of the Moon's surface.
- This contrast enhances the visibility of the lunar terrain and other features.
4. Astronaut Testimonies:
- Astronauts who have been on the Moon, such as the Apollo mission astronauts, have reported that the sky appears black from the lunar surface.
Conclusion:
The observed color of the sky from the Moon surface is black due to the absence of an atmosphere and the direct view of space. This black sky provides a striking contrast with the grayish lunar surface and allows for a clear view of celestial objects.

Modern periodic table has 18 vertical columns known as groups.

A combination of common salt and Iron filings is a mixture as there is no chemical reaction between them to form new substance.

Bio-gas is an excellent fuel as it contains up to 75% methane. It burns without smoke, leaves no residue like ash in wood, charcoal and coal burning. Its heating capacity is high. Bio-gas is also used for lighting.

The change of solid directly into vapours is called  Sublimation. The change of liquid state into vapours without coming to it's boiling point is called Evaporation. The latent heat of Vaporization is the heat required to change the state of 1 kg into vapours. Latent heat of fusion is the heat required to Change the state of 1 kg of solid  into liquid.

D is the correct option.Inexhaustible natural resource is a natural resource that will never run out. It will not be depleted and will continue to exist forever , such as water,sunlight, tidal energy, ocean energy and wind energy.