Factual Passage-2
Passage - 1
Photosynthesis is the cornerstone of life on Earth, enabling plants, algae, and some bacteria to convert sunlight into chemical energy. This process occurs in chloroplasts, where the pigment chlorophyll absorbs sunlight and uses it to combine carbon dioxide from the air with water from the soil. The result is glucose, a sugar that provides energy for growth, and oxygen, which is released into the atmosphere as a byproduct. Approximately 50% of the oxygen we breathe comes from photosynthetic organisms, with marine phytoplankton contributing a significant share. Without photosynthesis, life as we know it would cease, as it forms the base of most food chains.
The efficiency of photosynthesis depends on factors like light intensity, temperature, and carbon dioxide levels. In ideal conditions, plants maximize energy production, but excessive heat or drought can impair the process, reducing crop yields. Human activities, such as burning fossil fuels, increase atmospheric carbon dioxide, which could theoretically boost photosynthesis. However, this benefit is outweighed by climate change effects like rising temperatures and disrupted weather patterns. Deforestation further threatens this process by reducing the number of plants available to absorb carbon dioxide. Scientists are exploring bioengineering to enhance photosynthetic efficiency, potentially increasing food production to meet the demands of a growing global population. Protecting forests and reducing emissions remain critical steps to support this vital natural mechanism.
Questions:
1. Photosynthesis produces oxygen as a:
(a) Primary product
(b) Byproduct
(c) Fuel source
(d) Waste material
2. The pigment responsible for absorbing sunlight in photosynthesis is:
(a) Glucose
(b) Chlorophyll
(c) Carbon dioxide
(d) Phytoplankton
3. Excessive heat can negatively affect photosynthesis by:
(a) Increasing oxygen output
(b) Reducing crop yields
(c) Enhancing glucose production
(d) Boosting chlorophyll levels
4. Deforestation impacts photosynthesis by:
(a) Increasing carbon dioxide absorption
(b) Reducing the number of plants
(c) Improving light intensity
(d) Stabilizing temperature
5. A word from the passage meaning "to hinder or damage" is:
(a) Impair
(b) Enhance
(c) Absorb
(d) Contribute
Passage -2
The ozone layer, a region of Earth's stratosphere, plays a critical role in protecting life by absorbing most of the sun's harmful ultraviolet (UV) radiation. Composed of ozone molecules (O₃), it filters out UV-B rays, which can cause skin cancer, cataracts, and damage to marine ecosystems. This layer forms naturally when oxygen molecules (O₂) in the upper atmosphere are split by UV light and recombine into O₃. However, human-made chemicals like chlorofluorocarbons (CFCs), once widely used in refrigerants and aerosols, have depleted the ozone layer. These compounds release chlorine atoms when broken down by UV light, which then catalyze the destruction of ozone molecules.The 1987 Montreal Protocol, an international treaty, phased out CFCs and other ozone-depleting substances, leading to signs of recovery in the ozone layer. Despite this progress, challenges remain, as illegal production of CFCs has been detected in some regions, slowing the healing process. Scientists estimate that the ozone layer could return to pre-1980 levels by 2060 if compliance continues. Climate change also complicates recovery, as a warming planet alters stratospheric temperatures, affecting ozone formation. Meanwhile, UV exposure remains a public health concern in areas like Antarctica, where the ozone hole-a seasonal thinning-persists each spring, exposing life to higher radiation levels. Continued global cooperation is essential to safeguard this vital shield.
Questions:
1. The ozone layer protects life by absorbing:
(a) Infrared radiation
(b) Ultraviolet radiation
(c) Visible light
(d) Gamma rays
2. CFCs deplete the ozone layer by releasing:
(a) Oxygen atoms
(b) Chlorine atoms
(c) Nitrogen compounds
(d) Carbon molecules
3. The Montreal Protocol aimed to:
(a) Increase CFC production
(b) Phase out ozone-depleting substances
(c) Monitor UV radiation levels
(d) Reduce stratospheric temperatures
4. The ozone hole is described as:
(a) A permanent gap
(b) A seasonal thinning
(c) A global phenomenon
(d) A result of natural oxygen loss
5. A word from the passage meaning "to speed up or facilitate" is:
(a) Catalyze
(b) Depleted
(c) Phased
(d) Persists
