46. Mass of living matter at a trophic level in an area at any given time is called
Standing state
Standing crop
Humus
Detritus
Answer.2. Standing crop
Explanation:
Mass of living matter at a trophic level in an area at any time is called standing crop. They are measured as the mass of living organisms in a particular area. The standing crop of each tropic level can simply be known as biomass.
47. Hydrarch succession takes place in
Dry areas
Bare area
Wetter areas
None of the above
Answer.3. Wetter areas
Explanation:
A hydrarch succession is a form of plant succession that starts out in shallow water and eventually culminates in a forest. Usually, these types of successions are most likely to begin on shallow ponds, lakes, and other water bodies.
Hydrarch succession occurs in wet areas or water and the successional series progress from hydric to mesic conditions. A hydrosere is a plant succession that occurs in an area of freshwaters such as in Oxbow lakes and Kettle lakes.
48. Which of the following is a fossil fuel?
Oil
Coal
Natural gas
All of the above
Answer.2. Coal
Explanation:
Fossil fuel is a hydrocarbon-containing material formed underground from the remains of dead plants and animals that humans extract and burn to release energy for use. The main fossil fuels are coal, petroleum, and natural gas, which humans extract through mining and drilling.
49. Which of the following is not an inexhaustible form of energy?
Water
Wind
Solar
Fossil
Answer.3. Solar
Explanation:
Inexhaustible resources of energy are those sources, which will not exhaust in the future. These are unlimited. Examples – Air, and sunlight. Solar energy is available in nature in an unlimited amount.
50. Biogas contains mainly
Methane
Propane
Butane
Carbon dioxide
Answer.1. Methane
Explanation:
Biogas consists mainly of methane and carbon dioxide. It can also include small amounts of hydrogen sulfide, siloxanes, and some moisture.
51. The burning of fossil fuels releases a large amount of
Nitrogen into air
Sulfur into air
Carbon dioxide into the air
Oxygen into air
Answer.3. Carbon dioxide into the air
Explanation:
When fossil fuels are burned, they release large amounts of carbon dioxide, a greenhouse gas, into the air. Greenhouse gases trap heat in our atmosphere, causing global warming.
52. A poisonous gas given out of vehicle exhaust is
Methane
Ethane
Carbon dioxide
Carbon monoxide
Answer.4. Carbon monoxide
Explanation:
Vehicle exhaust fumes can irritate the eyes and respiratory tract and are a risk to health by breathing in. Carbon-fuelled engine fumes contain carbon monoxide, a poisonous gas.
53. The purest form of coal is
Anthracite
Lignite
Peat
Bitumen
Answer.1. Anthracite
Explanation:
Anthracite is the purest form of coal, having the highest degree of coalification, the highest carbon count and energy content, and the fewest impurities. Anthracite contains nearly 95% of carbon and it’s the purest form of coal than any other option.
54. Which one of the following gas is used as a refrigerant?
Freon
Teflon
Ethanol
Benzol
Answer.1. Freon
Explanation:
Freon is a non-combustible gas that is used as a refrigerant in air conditioning applications. This freon undergoes an evaporation process over and over again to help produce cool air that can be circulated throughout your AC system.
55. Loss of forest has led to
Erosion of fertile soil
Global warming
Loss of habitat of plants and animals
All of the above
Answer.4. All of the above
Explanation:
Loss of forests has led to wide-reaching problems like soil erosion, fewer crops, flooding, water cycle disruption, greenhouse gas emissions, changes in climatic conditions, and loss of biodiversity.
56. What are the consequences of excessive mining in an area?
Air and water pollution
Deforestation
Migration of large numbers of population
All of the above
Answer.4. All of the above
Explanation:
Environmental effects of mining can occur at local, regional, and global scales through direct and indirect mining practices. The effects can result in
Soil Erosion
Sinkholes
Loss of biodiversity
Deforestation
Migration of large numbers of population
Contamination of soil
Groundwater, and surface water by the chemicals emitted from mining processes.
57. Resources that are directly derived from nature are referred to as
Organic resources
Natural resources
Manmade resources
None of the above
Answer.2. Natural resources
Explanation:
Resources that are directly derived from nature are referred to as Natural resources.
Natural resources are naturally occurring materials that are useful to man or could be useful under conceivable technological, economic, or social circumstances or supplies drawn from the earth, supplies such as food, building and clothing materials, fertilizers, metals, water, and geothermal power.
58. Resources that take too long a period of time to be used as a resource are called as
Renewable resource
Non-renewable resource
Exhaustible resource
Inexhaustible resource
Answer.4. Inexhaustible resource
Explanation:
Resources that take too long a period of time to be used as a resource are called Inexhaustible resources.
An inexhaustible resource is a resource that never runs out or gets depleted. Some of such resources include wind, sun, solar energy, tides, and geothermal energy. They are mostly natural occurring resources hence they reappear naturally.
59. The fossil fuel that is derived from the dead remains of plants that grew some 250 million years ago is
Petroleum
Natural gas
Coal
LPG
Answer.1.
Explanation:
Fossil fuels are combustible hydrocarbons formed millions of years ago from the dead decaying plants and animals buried under sediment.
Coal is called a fossil fuel because it is derived from the dead remains of plants that grew some 250 million years ago.
60. A resource that cannot be replaced in a reasonably short time is usually referred to as
Renewable
Non-renewable
Natural
Man-made
Answer.2. Non-renewable
Explanation:
A resource that cannot be replaced in a reasonably short time is usually referred to as Non-renewable energy.
Nonrenewable energy resources include coal, natural gas, oil, and nuclear energy. Once these resources are used up, they cannot be replaced, which is a major problem for humanity as we are currently dependent on them to supply most of our energy needs.