The vegetation of savannah consists of grassland with scattered small trees, but extensive areas have no trees. The forest development in such areas is generally kept in check by one or more or a combination of some conditions. Which of the following are such conditions?
1. Burrowing animals and termites
2. Fire
3. Grazing herbivores
4. Seasonal rainfall
5. Soil properties
Select the correct answer using the code given below.
The question asks to identify the conditions that prevent extensive forest development in savannah ecosystems, which are characterized by grasslands with scattered small trees. We need to evaluate each given condition's role in limiting tree growth in such environments.
Based on this analysis, fire, grazing herbivores, and seasonal rainfall are the most significant conditions that keep forest development in check in savannahs.
Correct Option: C) 2, 3 and 4
With reference to the water on the planet Earth, consider the following statements:
1. The amount of water in the rivers and lakes is more than the amount of groundwater.
2. The amount of water in polar ice caps and glaciers is more than the amount of groundwater.
Which of the statements given above is/are correct?
The question asks us to compare the relative amounts of water stored in different reservoirs on Earth: rivers and lakes, groundwater, and polar ice caps/glaciers. To answer this, we need to recall the approximate distribution of Earth's freshwater resources.
B) 2 only. Statement 2 is correct because polar ice caps and glaciers hold the largest proportion of Earth's freshwater, significantly more than groundwater.
Consider the following statements:
1. Moringa (drumstick tree) is a leguminous evergreen tree.
2. The tamarind tree is endemic to South Asia.
3. In India, most of the tamarind is collected as minor forest produce.
4. India exports tamarind and seeds of moringa.
5. Seeds of moringa and tamarind can be used in the production of biofuels.
Which of the statements given above are correct?
1, 2, 4 and 5
3, 4 and 5
1, 3 and 4
1, 2, 3 and 5
The question asks us to identify the correct statements regarding Moringa and Tamarind. We need to evaluate each statement individually based on botanical and economic facts.
B) 3, 4 and 5 are the correct statements.
The question asks about the origin of black cotton soil in India. This requires knowledge of soil types, their formation processes, and the geological history of the Indian subcontinent.
Correct Option: B) Fissure volcanic rock. Black cotton soils (Regur soils) are primarily found in the Deccan Trap region of India. The Deccan Traps were formed by extensive volcanic eruptions that produced basaltic lava flows. The weathering of these basaltic rocks, which are a type of fissure volcanic rock, led to the formation of the characteristic black cotton soil.
With reference to recent developments regarding ‘Recombinant Vector Vaccines’, consider the following statements:
1. Genetic engineering is applied in the development of these vaccines.
2. Bacteria and viruses are used as vectors.
Which of the statements given above is/are correct?
The question asks about Recombinant Vector Vaccines. We need to evaluate two statements regarding their development process and the components used. Understanding the basic principles of genetic engineering and vaccine technology is key to answering this question.
Recombinant vector vaccines are a type of vaccine that uses a modified virus or bacterium (the vector) to deliver genetic material encoding an antigen from the pathogen against which immunity is desired. This modification involves inserting the gene for the antigen into the vector's genome. This process of inserting, deleting, or modifying genes is precisely what genetic engineering entails. Therefore, genetic engineering is fundamental to the development of recombinant vector vaccines.
In recombinant vector vaccines, a harmless virus or bacterium is engineered to carry genetic material (DNA or RNA) from the target pathogen. When this engineered vector is introduced into the body, it expresses the pathogen's antigen, triggering an immune response without causing the disease. Common viral vectors include adenoviruses, measles viruses, and vaccinia viruses. Bacterial vectors, such as attenuated Salmonella or Listeria, can also be used, though viral vectors are more common in current vaccine development.
Both statements accurately describe aspects of recombinant vector vaccines. Genetic engineering is the technique used to create these vaccines, and both bacteria and viruses can serve as the vectors to deliver the antigen-encoding genetic material.
C) Both 1 and 2
Both statements are correct. Recombinant vector vaccines are a product of genetic engineering, where genes encoding specific antigens are inserted into a harmless vector. These vectors can be either viruses (e.g., adenoviruses) or bacteria (e.g., attenuated Salmonella).
In the context of hereditary diseases, consider the following statements:
1. Passing on mitochondrial diseases from parent to child can be prevented by mitochondrial replacement therapy either before or after in vitro fertilization of the egg.
2. A child inherits mitochondrial diseases entirely from the mother and not from the father.
Which of the statements given above is/are correct?
The question asks to identify the correct statements regarding hereditary mitochondrial diseases. We need to evaluate each statement based on current scientific understanding of mitochondrial inheritance and mitochondrial replacement therapy.
The question asks about the context in which Bollgard I and Bollgard II technologies are mentioned. This requires knowledge of agricultural biotechnology and specific genetically modified crops.
B) developing genetically modified crop plants. Bollgard I and Bollgard II are types of genetically modified (GM) cotton. They incorporate genes from the bacterium Bacillus thuringiensis (Bt) into the cotton plant's genome. These genes produce proteins that are toxic to specific insect pests, such as the cotton bollworm, thereby providing the plant with built-in pest resistance. This process is a classic example of genetic engineering in agriculture.
In a pressure cooker, the temperature at which the food is cooked depends mainly upon which of the following?
1. Area of the hole in the lid
2. Temperature of the flame
3. Weight of the lid
Select the correct answer using the code given below.
1 and 2 only
2 and 3 only
1 and 3 only
1, 2 and 3
The temperature at which food cooks in a pressure cooker is primarily determined by the pressure inside the cooker. A higher pressure leads to a higher boiling point of water, thus allowing food to cook at a higher temperature than the normal boiling point (100°C at standard atmospheric pressure). We need to identify which factors influence this internal pressure.
Based on this analysis, both the area of the hole in the lid and the weight of the lid directly influence the maximum pressure inside the cooker, and consequently, the temperature at which food is cooked. The temperature of the flame affects the rate of cooking, not the maximum achievable temperature.
Both the area of the hole in the lid and the weight of the lid (specifically, the weight placed on the pressure regulating valve) determine the maximum pressure that can build up inside the cooker. A higher pressure leads to a higher boiling point of water and thus a higher cooking temperature.
Consider the following:
1. Bacteria
2. Fungi
3. Virus
Which of the above can be cultured in an artificial/synthetic medium?
1 and 2 only
2 and 3 only
1 and 3 only
1, 2 and 3
This question tests knowledge about the fundamental characteristics of microorganisms, specifically their ability to grow and reproduce in artificial laboratory conditions. Understanding the nutritional requirements and reproductive mechanisms of bacteria, fungi, and viruses is key to answering this question.
A) 1 and 2 only. Both bacteria and fungi are capable of independent metabolism and reproduction, allowing them to be grown in artificial culture media that provide the necessary nutrients. Viruses, being obligate intracellular parasites, require living host cells for replication and cannot be cultured in non-living artificial media.
Consider the following statements:
1. Adenoviruses have single-stranded DNA genomes whereas retroviruses have double-stranded DNA genomes.
2. Common cold is sometimes caused by an adenovirus whereas AIDS is caused by a retrovirus.
Which of the statements given above is/are correct?
The question asks us to evaluate two statements regarding viruses: their genetic material and the diseases they cause. We need to determine the correctness of each statement individually to find the right option.
Correct Option: B) 2 only