📘 Welcome
Hi User, you have selected Read Mode.
This is Time Free Mode for your convenience to understand every question as per your Ease and Time.
Here You get Answer and Details button. After mastering this mode, you can go for a test with Test Mode on the main page designed especially with Exam Features.
This is Time Free Mode for your convenience to understand every question as per your Ease and Time.
Here You get Answer and Details button. After mastering this mode, you can go for a test with Test Mode on the main page designed especially with Exam Features.
Q1. Regulation of body temperature is an example of:
Regulation of body temperature is a classic example of homeostasis. The body maintains its internal temperature within a narrow range despite changes in the external environment. This is achieved through mechanisms like sweating, shivering, and changes in blood flow. Homeostasis is the maintenance of a stable internal environment.
Q2. Plastic is considered:
Plastic is considered non-biodegradable because it cannot be broken down by microorganisms naturally. It persists in the environment for hundreds of years, causing pollution. Unlike organic materials, plastic does not decompose through biological processes.
Q3. Diatoms are important because they form:
Diatoms are important because they form a major part of phytoplankton. Phytoplankton are microscopic organisms that float in water bodies and form the base of the aquatic food chain. They produce a significant portion of the Earth’s oxygen through photosynthesis.
Q4. Coca alkaloids act primarily as:
Coca alkaloids (like cocaine) act primarily as stimulants. They increase activity in the central nervous system, leading to increased alertness, energy, and euphoria. They are not vaccines (which provide immunity), depressants (which slow down the CNS), or antibiotics (which fight bacteria).
Q5. Symbiotic relationship increases chances of:
A symbiotic relationship increases the chances of survival for the organisms involved. In mutualistic symbiosis, both partners benefit, making them better equipped to survive in their environment. The relationship provides advantages like food, shelter, or protection.
Q6. Diatomaceous earth is rich in:
Diatomaceous earth is rich in silica. It is formed from the accumulated cell walls (frustules) of dead diatoms. These cell walls are composed of silica (glass-like material). Diatomaceous earth is used in filtration, abrasives, and as an insecticide.
Q7. Composting helps in reducing:
Composting helps in reducing waste accumulation by converting organic waste into useful compost. It prevents organic waste from ending up in landfills, where it would produce methane and contribute to pollution. Composting also produces valuable soil amendments.
Q8. Immune system mainly involves:
The immune system mainly involves white blood cells (leukocytes). These cells are responsible for identifying and destroying pathogens, producing antibodies, and carrying out other immune functions. Red blood cells carry oxygen, while digestive and respiratory organs have other functions.
Q9. Osmosis is important in plants for:
Osmosis is important in plants for the absorption of water by root hairs from the soil. Water enters the root hairs by osmosis because the concentration of solutes is higher inside the root cells than in the soil. This is essential for the plant’s survival and growth.
Q10. The first line of defense of the body is:
The skin is the first line of defense of the body. It acts as a physical barrier that prevents pathogens from entering the body. It also produces antimicrobial substances and has a slightly acidic pH that inhibits the growth of many microorganisms.
Q11. Water moves from dilute to concentrated solution during:
During osmosis, water moves from a dilute solution (lower solute concentration) to a concentrated solution (higher solute concentration) across a selectively permeable membrane. This is a passive process that aims to equalize the concentration on both sides of the membrane.
Q12. In symbiosis, organisms live:
In symbiosis, organisms live together in close association. They share a habitat and often have a long-term relationship. This can be beneficial (mutualism), neutral (commensalism), or harmful (parasitism) to one or both partners. The key feature is that they live together.
Q13. Antibodies are produced by:
Antibodies are produced by white blood cells, specifically by B lymphocytes (a type of white blood cell). When B cells encounter an antigen, they differentiate into plasma cells that produce large quantities of antibodies. Platelets are involved in blood clotting, red blood cells carry oxygen, and plasma is the liquid part of blood.
Q14. Homeostasis is essential for:
Homeostasis is essential for the survival of the organism. Without the maintenance of stable internal conditions, cells would not function properly, and the organism would not be able to survive. Homeostasis is necessary for all life processes, including growth, movement, and reproduction.
Q15. Diatoms store food mainly in the form of:
Diatoms store food mainly in the form of oil. This oil is a type of lipid that serves as an energy reserve. Some diatoms can accumulate significant amounts of oil, which is of interest for biofuel production. Starch is found in green algae, glycogen in animals, and proteins are not the main storage form.
Q16. The cell wall of diatoms is called:
The cell wall of diatoms is called a frustule. It is made of silica (glass-like material) and consists of two overlapping halves. The frustule is highly ornamented and unique to diatoms. Cortex is found in plants, periderm is plant bark, and cuticle is the waxy layer on plant surfaces.
Q17. Coelenterates belong to the phylum:
Coelenterates belong to the phylum Coelenterata (also called Cnidaria). This phylum includes hydra, jellyfish, sea anemones, and corals. They are characterized by a sac-like body plan with a single opening. Mollusca includes snails, Arthropoda includes insects, and Annelida includes earthworms.
Q18. Lichen is an example of:
Lichen is an example of symbiosis, specifically mutualism. A lichen is made up of a fungus and an algae (or cyanobacterium) living together. The fungus provides shelter and nutrients, while the algae provides food through photosynthesis. Both partners benefit from this relationship.
Q19. Cannabis sativa mainly affects the:
Cannabis sativa mainly affects the nervous system. The psychoactive compound THC (tetrahydrocannabinol) interacts with cannabinoid receptors in the brain, altering perception, mood, and cognition. It does not primarily affect the digestive, respiratory, or circulatory systems.
Q20. Composting converts waste into:
Composting converts organic waste into humus-rich manure. The final product is a dark, nutrient-rich material that improves soil health. It is not chemical salts, a liquid fertilizer solution, or just gases (though some gases are released during the process).
Q21. Vermicompost is best described as:
Vermicompost is best described as organic manure. It is produced from organic waste processed by earthworms. It is natural and contains nutrients in a form that plants can easily absorb. It is not chemical, mineral, or synthetic.
Q22. Antibody–antigen reaction is:
Antibody–antigen reaction is specific. Each antibody is designed to bind to a specific antigen, much like a lock and key. This specificity is the basis of the immune system’s ability to target particular pathogens. The reaction is not random or merely chemical in a general sense.
Q23. Immunization helps in building:
Immunization helps in building long-term protection against specific diseases. The vaccine triggers the immune system to produce memory cells that remember the pathogen. If the person is exposed to the pathogen later, the immune system responds quickly and effectively, preventing the disease.
Q24. Vermicomposting uses:
Vermicomposting uses earthworms to convert organic waste into nutrient-rich compost. The worms consume organic matter and excrete it as vermicast, which is excellent fertilizer. Termites, beetles, and ants are not used in vermicomposting.
Q25. Coelenterates show:
Coelenterates show radial symmetry. This means their body can be divided into equal halves by any plane passing through the central axis. This symmetry is adapted for a sessile or drifting lifestyle. Asymmetry is seen in sponges, bilateral symmetry in most animals.
Q26. The immune response is triggered by:
The immune response is triggered by antigens. Antigens are foreign substances that the immune system recognizes as non-self. They stimulate the production of antibodies and other immune responses. Enzymes, antibodies, and hormones are not the triggers; they are parts of or products of the response.
Q27. Non-biodegradable waste causes:
Non-biodegradable waste causes environmental pollution. Items like plastics, metals, and glass persist in the environment for a long time, contaminating soil, water, and air. They do not form compost, improve soil, or purify water.
Q28. Diatoms are primary producers in:
Diatoms are primary producers in aquatic ecosystems. They form the base of the food chain in oceans, lakes, and rivers, converting sunlight into energy through photosynthesis. They are not primary producers in deserts, forests, or grasslands.
Q29. Passive immunity is provided by:
Passive immunity is provided by antibodies. In passive immunity, antibodies are transferred from one individual to another, providing immediate but temporary protection. This occurs naturally (mother to child through breast milk) or artificially (antibody injections).
Q30. Antibodies are also called:
Antibodies are also called immunoglobulins. They are glycoproteins produced by the immune system. The term “immunoglobulin” refers to their role in immunity. Antitoxins are a type of antibody, enzymes are catalysts, and hormones are signaling molecules.
Q31. Diatoms release oxygen during:
Diatoms release oxygen during photosynthesis. Like plants, they use sunlight, water, and carbon dioxide to produce food and release oxygen as a byproduct. This contributes significantly to the Earth’s oxygen supply.
Q32. Homeostasis in humans is controlled mainly by:
Homeostasis in humans is controlled mainly by the nervous and endocrine systems. These systems work together to detect changes in the internal environment and bring about corrective responses. The nervous system provides fast responses, while the endocrine system provides slower, longer-lasting responses.
Q33. Osmosis occurs due to difference in:
Osmosis occurs due to a difference in solute concentration across a selectively permeable membrane. Water moves from a region of lower solute concentration to a region of higher solute concentration to equalize the concentrations. Pressure, temperature, and volume are not the direct causes.
Q34. Archaebacteria lack a:
Archaebacteria lack a true nucleus. They are prokaryotes, meaning they do not have a membrane-bound nucleus. Their genetic material is free in the cytoplasm. They do have a cell wall, ribosomes, and a cell membrane.
Q35. Archaebacteria differ from eubacteria mainly in:
Archaebacteria differ from eubacteria mainly in cell wall composition. Archaebacteria have cell walls that lack peptidoglycan, a key component of eubacterial cell walls. Their cell walls contain other molecules like pseudomurein. This is a fundamental difference.
Q36. Vermicompost contains more:
Vermicompost contains more organic matter compared to other soil amendments. It is rich in humus and nutrients like nitrogen, phosphorus, and potassium. It does not contain metals, chemical toxins, or plastics.
Q37. Halophiles live in environments with high:
Halophiles live in environments with high salinity (salt concentration). They thrive in places like salt lakes, salt pans, and other saline conditions. “Halo” means salt, and “phile” means loving, so halophiles are salt-loving organisms.
Q38. Diatoms reproduce mainly by:
Diatoms reproduce mainly by binary fission (asexual reproduction). The parent cell divides into two daughter cells, each receiving one of the two frustules (silica cell walls). The daughter cells then produce a new smaller half. Spore formation, budding, and fragmentation are not the main modes of reproduction in diatoms.
Q39. Biodegradable waste is mainly decomposed by:
Biodegradable waste is mainly decomposed by microorganisms (bacteria and fungi). These organisms break down the organic material into simpler substances through metabolic processes. Physical and chemical agents are not the primary decomposers.
Q40. Extreme hot springs are inhabited by:
Extreme hot springs are inhabited by thermophiles (heat-loving organisms). These are organisms that can survive and thrive at high temperatures, often above 60°C. Halophiles live in salty environments, methanogens produce methane, and cyanobacteria are photosynthetic.
Q41. Symbiosis is a type of:
Symbiosis is a type of association between organisms of different species. It involves living together in close contact. It is not specifically parasitism (one benefits, one is harmed), competition, or predation.
Q42. Archaebacteria are important for:
Archaebacteria are important for methane formation. Methanogens are a type of archaebacteria that produce methane as a byproduct of their metabolism. They are found in swamps, marshes, and the digestive tracts of ruminants.
Q43. Antigens usually are:
Antigens are usually proteins or polysaccharides (complex carbohydrates). These molecules are often found on the surface of pathogens and are recognized by the immune system. Lipids, hormones, and vitamins are typically not antigens.
Q44. Nicotine is the active compound present in:
Nicotine is the active compound present in tobacco. It is an alkaloid that is highly addictive and stimulates the central nervous system. Opium contains morphine, cannabis contains THC, and coca contains cocaine.
Q45. Opium is obtained from which plant part of Papaver somniferum?
Opium is obtained from the seed pod (capsule) of Papaver somniferum (the poppy plant). The latex is collected by making incisions in the unripe seed capsules. The root, leaf, and stem are not the sources of opium.
Q46. Earthworms improve soil by increasing:
Earthworms improve soil by increasing aeration. As they burrow through the soil, they create channels that allow air and water to penetrate. This improves soil structure and oxygen availability for plant roots. They do not increase acidity, salinity, or temperature.
Q47. Vermicompost helps plants by supplying:
Vermicompost helps plants by supplying essential nutrients like nitrogen, phosphorus, and potassium. These nutrients are in forms that plants can easily absorb. While vermicompost may contain some enzymes and hormones, its primary benefit is as a nutrient source.
Q48. Methanogens produce:
Methanogens produce methane. They are a type of archaebacteria that thrive in anaerobic conditions and produce methane gas as a metabolic byproduct. They are found in places like swamps, marshes, and the digestive tracts of animals.
Q49. Osmosis takes place only in presence of:
Osmosis takes place only in the presence of a semi-permeable membrane (selectively permeable membrane). This membrane allows water molecules to pass but restricts the passage of solute molecules. A cell wall is not semi-permeable in the same way, and light and energy are not required for osmosis.
Q50. Immunity obtained after vaccination is:
Immunity obtained after vaccination is artificial active immunity. It is “artificial” because it is acquired through medical intervention (vaccination). It is “active” because the body’s immune system is actively involved in producing antibodies and memory cells. The vaccine stimulates the body to mount an immune response.