SCHOOL OF SOCIOLOGY
Quaid-e-Azam University, Islamabad
Course: Introduction to Natural Science
Submitted to:
Ma’am Ayesha Kanwal
Submitted by:
Ayesha Sana
1. Hepatitis: Types, Causes, Prevention, and Cure
Hepatitis is the inflammation of the liver, usually caused by viral infections,
excessive alcohol use, or autoimmune conditions. There are five main types:
Hepatitis A, B, C, D, and E.
● Hepatitis A and E are spread through contaminated food or water.
● Hepatitis B, C, and D are transmitted through contact with infected blood
or bodily fluids.
Symptoms include fatigue, jaundice, abdominal pain, and nausea.
● Prevention includes maintaining hygiene, avoiding shared needles,
practicing safe sex, and getting vaccinated (for Hepatitis A and B).
● Cure: Hepatitis A and E usually resolve without treatment. Chronic
Hepatitis B and C may require antiviral medications and regular monitoring.
Early diagnosis and healthy lifestyle choices are key to managing the
disease. In severe cases, liver transplants may be needed. Global
vaccination and awareness efforts are crucial in reducing the burden of
hepatitis.
2. Role of Remote Sensing and GIS in Environmental Science
Remote Sensing and GIS (Geographic Information Systems) play vital roles in
modern environmental science.
● Remote Sensing uses satellite or aerial imagery to collect data about
Earth’s surface, such as land use, vegetation, and water bodies.
● GIS helps analyze, visualize, and interpret spatial data to identify patterns
and trends.
Together, they are used to monitor deforestation, track climate change,
predict natural disasters, and study pollution levels.
For example, during floods or wildfires, remote sensing provides real-time
imagery while GIS models help in planning evacuation or restoration
efforts.
They support sustainable land management, urban planning, and disaster
mitigation strategies.
These tools provide accurate and large-scale data over time, making them
indispensable for researchers, environmentalists, and policy-makers.
By integrating data from various sources, they ensure informed decisions
are made to protect and conserve the environment effectively.
3. Role of Carbohydrates and Vitamins in the Body
Carbohydrates and vitamins are essential nutrients needed for maintaining body
health and energy.
● Carbohydrates are the body’s primary energy source. They break down
into glucose, which fuels muscles, the brain, and vital organs. Complex
carbs, like whole grains, also provide fiber, aiding digestion and stabilizing
blood sugar.
● Vitamins are micronutrients that support various physiological functions.
○ Vitamin A helps with vision,
○ Vitamin C boosts immunity,
○ Vitamin D strengthens bones,
○ Vitamin B complex supports metabolism and nerve function.
Both nutrients are essential for growth, repair, and disease
prevention.
A deficiency in vitamins can lead to serious health problems like
scurvy (Vitamin C) or rickets (Vitamin D), while a lack of carbs can
cause fatigue and dizziness.
A balanced diet containing fruits, vegetables, whole grains, and lean
proteins ensures the body gets adequate amounts of carbohydrates
and vitamins for optimal functioning.
4. Applications of Electromagnetic Radiations
Electromagnetic radiations have wide-ranging applications in science, health,
and technology:
● Ultraviolet (UV):
1. Sterilizing medical tools.
2. Detecting forged documents and currency.
● Infra-red (IR):
1. Thermal imaging in night-vision cameras.
2. Remote controls for electronic devices.
● Microwaves:
1. Cooking food in microwave ovens.
2. Used in satellite and mobile communication.
● Radio waves:
1. Broadcasting radio and television signals.
2. Used in wireless communication systems like walkie-talkies.
● X-rays:
1. Used in hospitals for imaging bones and detecting fractures.
2. Airport security scans for inspecting luggage.
These radiations, while invisible, have become essential to modern
life. Each type operates at different wavelengths and frequencies,
making them suitable for specific applications. Proper handling is
necessary as excessive exposure, especially to UV and X-rays, can
be harmful.
5. Fog vs. Smog: Causes, Effects, and a Technological Solution
Fog is a natural weather phenomenon caused by condensation of water droplets
near the ground, reducing visibility.
Smog, however, is a harmful mix of fog and pollutants like nitrogen oxides,
particulate matter, and ground-level ozone.
● Causes: Vehicle emissions, industrial pollution, burning fossil fuels, and
weather conditions.
● Effects on Health:
○ Irritation of eyes, nose, and throat.
○ Worsening of asthma and respiratory conditions.
○ Increased risk of lung and heart diseases.
Smog not only affects health but also reduces visibility, causing
accidents and disrupting air travel.
Latest Technology – Smog Towers:
Smog towers are large air purification systems that suck in polluted
air and release cleaner air. Using technologies like electrostatic
filtration, they trap particulate matter (PM2.5 and PM10).
They are being used in cities like Delhi to reduce urban air pollution
and improve air quality.
6. What is Biosphere? Write a Note on Energy Resources Available in
Biosphere
The biosphere is the zone of life on Earth, encompassing all living organisms
and the ecosystems they form. It includes land (lithosphere), water
(hydrosphere), and air (atmosphere) where life exists. The biosphere is crucial
for maintaining ecological balance and supporting biodiversity.
Energy resources in the biosphere are both renewable and non-renewable.
● Renewable sources include sunlight (solar energy), wind, water
(hydropower), and biomass (plant and animal matter). These are naturally
replenished and sustainable if used wisely.
● Non-renewable sources like coal, petroleum, and natural gas are derived
from ancient biological material but cannot be replaced in a short time.
Humans depend on these energy resources for electricity, transportation,
agriculture, and industry. Overexploitation of non-renewable sources leads to
pollution and climate change. Therefore, sustainable management of energy
from the biosphere is essential for environmental protection and long-term
survival.
7. Different Layers of Atmosphere, Basis of Classification, Auroras and
Satellites
The Earth's atmosphere is divided into five main layers based on temperature
variations:
1. Troposphere: Closest to Earth, where weather occurs.
2. Stratosphere: Contains the ozone layer.
3. Mesosphere: Meteors burn up here.
4. Thermosphere: Auroras form here due to solar wind and Earth’s magnetic
field.
5. Exosphere: Outermost layer, merging into space.
These layers are classified based on temperature gradients, altitude, and
chemical composition.
● Auroras (Northern and Southern Lights) occur in the thermosphere when
solar particles collide with atmospheric gases, creating glowing lights.
● Satellites orbit in the thermosphere and exosphere, where air
resistance is low. These include weather, communication, and GPS
satellites.
Understanding these layers helps scientists monitor weather, climate, and space
activity. It also aids in protecting technology and life from harmful space radiation
and atmospheric changes.
8. Difference Between Network and Internet
A network is a group of interconnected computers and devices that can share
resources like files, printers, and internet connections. Networks can be Local
Area Networks (LAN), confined to a small area like an office or home, or Wide
Area Networks (WAN), spread across large distances.
The Internet, on the other hand, is a global system of interconnected computer
networks. It is the world’s largest WAN that connects millions of private, public,
academic, and business networks worldwide.
Key Differences:
● A network can be small and private; the internet is vast and public.
● A network may not require internet access to function, but internet relies on
interconnected networks.
● Internet allows global communication via websites, email, and social
media.
In summary, all internet connections are networks, but not all networks are part of
the internet. The internet is like a massive collection of interconnected smaller
networks.
9. Difference Between Renewable and Non-Renewable Sources of Energy
and Explanation of Wind, Solar, and Biofuels
Renewable energy sources are naturally replenished and environmentally
friendly, such as wind, solar, and biomass. Non-renewable sources like coal, oil,
and natural gas are limited and cause pollution when used.
Key Differences:
● Renewable sources are sustainable; non-renewable will eventually
deplete.
● Renewable energy is clean; non-renewable contributes to climate change.
Wind Energy: Produced by converting wind's kinetic energy into electricity using
turbines. It’s clean and abundant but depends on weather.
Solar Energy: Captured from sunlight using solar panels. It’s widely available,
especially in sunny regions, and reduces reliance on fossil fuels.
Biofuels: Derived from organic materials like plants, algae, or animal waste.
Examples include ethanol and biodiesel. They are renewable and can replace
gasoline in vehicles.
These renewable sources are key to sustainable development and reducing
environmental pollution.
10. Vaccines: Types, Side Effects, and Effectiveness
Vaccines are biological substances that stimulate the immune system to
recognize and fight infectious diseases. They prepare the body to defend itself
without causing the disease.
Types of Vaccines:
1. Live attenuated vaccines (e.g., MMR): Weakened form of the virus.
2. Inactivated vaccines (e.g., Hepatitis A): Killed virus.
3. mRNA vaccines (e.g., COVID-19): Teach cells to make a protein that
triggers an immune response.
4. Subunit vaccines: Use pieces of the virus (e.g., HPV vaccine).
5. Toxoid vaccines: Prevent diseases caused by bacterial toxins (e.g.,
Tetanus).
Side Effects are usually mild: fever, pain at the injection site, or fatigue. Rarely,
allergic reactions occur.
Effectiveness: Vaccines have eradicated or reduced many deadly diseases like
smallpox and polio. They are safe, cost-effective, and essential for public health.
Widespread vaccination protects communities through herd immunity.
11. Factors Affecting Climate Variation in a Place
Climate is the long-term pattern of weather conditions in a particular area.
Several factors influence climate variation:
● Latitude: Places near the equator are warmer due to direct sunlight, while
polar regions are colder.
● Altitude: Higher altitudes have cooler temperatures.
● Distance from Oceans: Coastal areas have milder climates, while inland
regions experience extreme temperatures.
● Ocean Currents: Warm or cold currents influence the temperature and
humidity of nearby regions.
● Topography: Mountains can block wind and rain, creating dry areas (rain
shadows).
● Wind Patterns: Global wind belts distribute heat and moisture.
● Human Activities: Urbanization and deforestation alter temperature and
precipitation.
● Presence of Vegetation: Dense forests regulate local temperatures and
humidity.
These factors interact to create distinct climates around the world. Understanding
them helps in climate prediction, agriculture planning, and disaster preparedness,
especially in the face of global warming.
12. Difference Between a Star and a Planet
Stars and planets are both celestial bodies, but they differ in many ways:
● Stars are massive, glowing spheres of hot gases (mainly hydrogen and
helium) that produce light and heat through nuclear fusion. The Sun is an
example.
● Planets are non-luminous bodies that orbit stars. They do not produce
their own light but reflect the light of their star.
● Stars are usually larger and have high temperatures. Planets are cooler
and come in different types—rocky (like Earth) or gaseous (like Jupiter).
● Planets orbit stars in defined paths, while stars remain relatively fixed in
constellations.
● Stars are the center of solar systems, while planets are members of those
systems.
In summary, a star is a shining body that emits energy, while a planet is a body
that revolves around a star and depends on it for light and heat.
13. Sequence of Atmospheric Strata and Factors Influencing It
The Earth’s atmosphere is divided into five main strata based on temperature
changes:
1. Troposphere (0–12 km): Weather events occur here.
2. Stratosphere (12–50 km): Contains ozone layer; planes fly here.
3. Mesosphere (50–80 km): Meteors burn here.
4. Thermosphere (80–700 km): Auroras occur; space shuttles orbit here.
5. Exosphere (700 km+): Merges into outer space; very thin air.
Factors Influencing Stratification:
● Temperature gradient is the main basis for classification—some layers
increase in temperature with altitude, others decrease.
● Composition of gases, air pressure, and density also affect layering.
● Solar radiation interacts differently in each layer, influencing its properties.
Understanding these layers helps scientists in weather forecasting, climate
studies, and satellite deployment. The stratosphere’s ozone layer, for example,
shields us from harmful UV radiation, while the thermosphere supports satellite
and radio communications.
14. Water Cycle and Processes Involved
The water cycle, or hydrological cycle, is a continuous process by which water
moves through the environment. It plays a vital role in maintaining life on Earth.
Key processes include:
1. Evaporation: Sun heats water in oceans, lakes, and rivers, turning it into
vapor.
2. Transpiration: Plants release water vapor into the air.
3. Condensation: Water vapor cools in the atmosphere to form clouds.
4. Precipitation: Water returns to Earth as rain, snow, sleet, or hail.
5. Infiltration and Runoff: Water soaks into the ground or flows into rivers
and oceans.
This cycle is driven by solar energy and gravity. It purifies water, regulates
weather, supports agriculture, and sustains ecosystems. Human activities like
deforestation and pollution can disrupt the cycle, leading to droughts or floods.
Conservation and sustainable water use are essential to maintaining a balanced
water cycle.
15. Solar Eclipse and Lunar Eclipse Explained
Solar Eclipse occurs when the Moon comes between the Earth and the Sun,
blocking the Sun’s light either partially or completely for a short time.
● It can only happen during a new moon phase.
● There are three types: total, partial, and annular.
● People in the eclipse path experience temporary darkness during the day.
Lunar Eclipse happens when the Earth comes between the Sun and the
Moon, casting a shadow on the Moon.
● It occurs during a full moon phase.
● Types include total, partial, and penumbral eclipses.
● The Moon may appear reddish during a total lunar eclipse—this is called a
“blood moon.”
Eclipses are natural phenomena and pose no danger if observed safely.
However, viewing a solar eclipse without protection can damage the eyes. These
events have helped scientists study the Sun’s corona and understand orbital
mechanics.
16. What is Acid Rain? Causes and Prevention
Acid rain is rainfall that has been made acidic due to the presence of pollutants
in the atmosphere, mainly sulfur dioxide (SO₂) and nitrogen oxides (NOₓ). When
these gases are released from burning fossil fuels, they react with water vapor in
the air to form sulfuric and nitric acids. These acids mix with rainwater and fall to
Earth as acid rain.
Causes include:
● Emissions from factories, power plants, and vehicles
● Burning of coal and oil
● Industrial processes
Effects:
● Damages buildings and monuments
● Harms aquatic life by lowering pH in water bodies
● Weakens trees and plants
● Affects soil health and crop yields
Prevention:
● Use cleaner fuels and renewable energy
● Install scrubbers in factories to filter emissions
● Promote public transportation and electric vehicles
● Enforce environmental regulations
Public awareness and international cooperation are essential to combat acid rain
and protect the environment.
17. Factors Responsible for Environmental Pollution
Environmental pollution refers to the contamination of natural surroundings due
to harmful human activities. It affects air, water, soil, and even noise levels,
endangering ecosystems and human health.
Major factors include:
● Industrialization: Emission of smoke, chemicals, and toxic waste
● Deforestation: Reduces oxygen production and increases carbon dioxide
● Urbanization: Increases garbage, sewage, and land misuse
● Vehicle Emissions: Release pollutants like CO, NOx, and particulate
matter
● Agricultural Activities: Use of pesticides and fertilizers pollutes water and
soil
● Plastic Waste: Non-biodegradable plastics harm wildlife and oceans
● Mining and Oil Spills: Destroy landscapes and marine ecosystems
Consequences: Climate change, global warming, respiratory diseases,
waterborne illnesses, and biodiversity loss.
To reduce pollution, we must adopt sustainable practices, implement strict
environmental laws, use green technologies, and educate people about
conservation and responsible consumption.
18. What is Ozone Depletion and How Can It Be Prevented?
Ozone depletion is the thinning of the ozone layer in the Earth’s stratosphere
due to harmful chemicals, mainly chlorofluorocarbons (CFCs), halons, and
other ozone-depleting substances (ODS). The ozone layer is crucial because it
absorbs most of the Sun’s harmful ultraviolet (UV) radiation.
Causes:
● Use of CFCs in air conditioners, refrigerators, and aerosol sprays
● Industrial processes and fire extinguishers releasing halons
● Certain pesticides and solvents
Effects:
● Increased UV radiation leads to skin cancer, cataracts, and immune
system damage
● Affects plant growth and aquatic ecosystems
● Contributes to global warming indirectly
Prevention:
● Ban and phase out CFCs and other ODS (as per the Montreal Protocol)
● Use eco-friendly products and appliances
● Raise awareness about the importance of ozone protection
● Promote research into ozone-safe technologies
Protecting the ozone layer is essential for shielding life on Earth from harmful
solar radiation.
19. Effects of Earth’s Rotation and Revolution
The Earth exhibits two main motions: rotation on its axis and revolution around
the Sun. Both have important effects on our planet.
Rotation:
● Earth rotates once every 24 hours, causing day and night.
● It influences the Coriolis effect, which affects wind and ocean current
patterns.
● Determines time zones and sunrise/sunset timings.
Revolution:
● Earth revolves around the Sun once a year (365.25 days), causing
seasons.
● The tilt of Earth’s axis (23.5°) means different areas receive varying
amounts of sunlight throughout the year.
● It also influences the length of days and nights in different seasons.
These motions are vital for climate, agriculture, and life cycles. Without them, we
wouldn’t experience seasonal changes, and ecosystems would not function as
they do. Understanding these movements helps scientists predict weather,
seasons, and astronomical events.
20. Short Note on the Greenhouse Effect
The greenhouse effect is a natural process where certain gases in the Earth’s
atmosphere trap heat, keeping the planet warm enough to sustain life. These
greenhouse gases (GHGs) include carbon dioxide (CO₂), methane (CH₄),
nitrous oxide (N₂O), and water vapor.
Sunlight enters the Earth’s atmosphere, and the surface absorbs it, radiating
some energy back as infrared heat. Greenhouse gases trap part of this heat,
preventing it from escaping into space.
Positive role: Maintains Earth’s average temperature, supporting ecosystems
and agriculture.
Problem: Human activities like burning fossil fuels, deforestation, and
industrialization increase GHG levels, enhancing the greenhouse effect and
causing global warming.
Consequences:
● Rising sea levels
● Melting glaciers
● More frequent extreme weather
● Shifting climate patterns
Solutions: Reduce carbon emissions, adopt renewable energy, conserve forests,
and promote energy-efficient practices. Addressing the enhanced greenhouse
effect is crucial for environmental sustainability.
