General Science — Past Papers — Part 4 MCQs with Explanations

A mature, large ovary and seed are characteristics of a fruit . A fruit is the mature ovary of a plant , which contains seeds . It typically surrounded by a fleshy, edible pulp .

Root hairs are tiny tubular outgrowths of roots in plants. They increase the surface area of roots for efficient absorption. Their main function is to absorb water, mineral salts, and gases from the soil. They do not perform photosynthesis or reproduction.

A sphygmomanometer is a medical device used to measure blood pressure. It consists of an inflatable cuff and a pressure gauge.

Blood vessels and capillaries are part of the circulatory system. They transport blood throughout the body , ensuring oxygen and nutrients reach tissues. Veins specifically carry blood towards the heart, while arteries carry blood away from the heart. Capillaries connect arteries and veins and allow exchange of oxygen, nutrients, and waste .

Bile , produced by the liver and stored in the gallbladder . It breaks down fats into smaller particles , making it easier for enzymes to digest them . This process is called emulsification .

Lung cancer is a disorder of the respiratory tract caused by uncontrolled cell division. It leads to the formation of abnormal masses or tumors in the lungs. Major types include Small Cell Lung Cancer (SCLC) and Non-Small Cell Lung Cancer (NSCLC). Risk factors : Smoking, air pollution, genetic predisposition. Symptoms may include cough, chest pain, shortness of breath, and coughing blood .

Air is essential for plants because they need gases from the air for survival and growth . Plants take carbon dioxide (CO₂) from the air during photosynthesis to make their food. They also use oxygen (O₂) from the air for respiration to release energy. Without air , plants cannot perform important life processes.

Dilution refers to the process of decreasing the concentration of a solution by adding more solvent. While ionisation involves the formation of ions from molecules in a solution .

Citric acid is a natural preservative found in many fruits, particularly in citrus fruits like lemons, oranges, and grapefruits. It's responsible for their sour taste and is also used as a food additive. Other fruits like mangoes, grapes, and strawberries also contain citric acid, although in smaller amounts. The presence of citric acid gives these fruits their characteristic sour taste.

When light is focused in front of the retina , it creates a blurred image, indicating nearsightedness (myopia). This occurs because the eyeball is too long or the cornea is too steep. It causing light to focus before reaching the retina.

The renewable energy sources are : Water energy Wind energy Tidal energy Solar energy Hydroelectric Ocean energy Geothermal energy Biomass Biogas The non-renewable energy sources are : Fossil fuels or Hydrocarbon fuel (Oil, Natural gas, Coal) Nuclear energy

Gear is a wheel with teeth along its edge that interlock with another gear to transmit motion and force . Gears are used to increase or decrease speed, change direction, or increase torque in machines. Common in clocks, bicycles, vehicles, and industrial machines.

Bases are substances that have a soapy or slippery feel when touched. This property occurs because bases react with oils on the skin , giving a soap-like texture . Many bases also turn red litmus paper blue in chemical tests. Common bases are used in cleaning agents, soaps, and detergents .

Copper is a chemical element with the symbol Cu and atomic number 29. It is a soft, malleable, and ductile metal with a reddish-orange color. The some major elements with their symbols : Hydrogen - H Sodium - Na Carbon - C Nitrogen - N Oxygen - O Fluorine - F Chlorine - Cl Potassium - K Helium - He Neon - Ne Calcium - Ca Sulphur - S Phosphorus - P Aluminium - Al Magnesium - Mg Iron - Fe

A solid has both a definite shape and a definite volume . The particles in solids are tightly packed and only vibrate in fixed positions. Examples include iron, wood, stone, and ice . Additional information : A liquid has a definite volume but no definite shape. A gas has neither definite shape nor definite volume.

Translocation is the process by which food made in the leaves moves to other parts of the plant through the phloem . In plants, food is produced in the leaves through photosynthesis. This prepared food must be transported to other parts like roots, stems, and fruits .

The Canines are pointed teeth that are adapted for tearing and slashing . Teeth are specialized structures in the mouth for biting, tearing, and chewing food . Humans have different types of teeth: incisors, canines, premolars, and molars. Humans have 4 canines (2 upper, 2 lower) used for tearing meat .

A solar day is the time taken by the Earth to complete one full rotation on its axis relative to the Sun. Length of a solar day = 24 hours = 1,440 minutes Length of a sidereal day = 23 hours 56 minutes 4 seconds Earth rotates approximately 360° relative to the Sun in a solar day Lunar day = ~ 24 hours 50 minutes (Moon’s rotation relative to Sun)

The iris is the colored part of the eye that controls the size of the pupil . By adjusting the pupil size, it regulates the amount of light entering the eye , just like a camera diaphragm. Pupil dilation occurs in low light, letting in more light. Pupil contraction occurs in bright light, protecting the retina from damage.

Sound waves first enter the ear through the Ear Canal . It is also known as the external auditory meatus . From there, they travel to the eardrum , then to the cochlea , and finally to the auditory nerve .

Transmission is the process where light passes through a material without being absorbed or reflected. The light may pass completely unchanged if the material is transparent . Additional information : Reflection – Light bounces back from a surface Absorption – Light is taken in by a material and converted to heat Refraction – Light bends while passing from one medium to another (like air to water)

Gears can: Change speed: Gears can increase or decrease Change direction : Gears can change the direction of rotation Change force : Gears can increase or decrease the force However, gears cannot change the fulcrum , which is the pivot point or axis of rotation.

Fuel stores energy in the form of chemical bonds . When fuel burns in the engine, this chemical energy is converted into mechanical energy to move the car. Gasoline, diesel, and natural gas are common fuels storing chemical energy . The process of burning fuel to release energy is called combustion .

Limiting factors are environmental conditions that restrict the growth, abundance, or distribution of organisms . They determine which species can survive and how many individuals of each species can exist in an ecosystem. Limiting factors can be abiotic (non-living) like sunlight, water, or temperature . They can also be biotic (living) like competition, predation, or disease .

During swallowing, the epiglottis (a flap of cartilage) folds down. It closes the opening of the trachea (windpipe) so that food enters the esophagus instead of the airway. This protective mechanism prevents choking and food entering the lungs.

Stomata are tiny pores present mainly on the surface of leaves . They allow carbon dioxide (CO₂) to enter the plant for photosynthesis and release oxygen . Stomata are controlled by guard cells , which open and close the pores.

The outer ear ( pinna and ear canal ) collects sound vibrations from the environment. These vibrations travel through the auditory canal to the eardrum (tympanic membrane). Additional information : Main Parts of the Ear Outer Ear – Pinna and auditory canal Middle Ear – Eardrum and three ossicles (malleus, incus, stapes) Inner Ear – Cochlea and semicircular canals (hearing and balance)

Nitrogen (N2) makes up about 78% of the Earth's atmosphere. Making it the most abundant gas in the atmosphere. It is followed by oxygen (~21%), with other gases in much smaller amounts.

The symbolic representation of a molecule of a compound is called a formula . It uses symbols and numbers to represent the composition of the molecule. For example, the formula for water is H₂O , indicating two hydrogen atoms and one oxygen atom.

An atom is the smallest possible particle of an element that can combine to form new compounds. Atoms are the building blocks of matter, and they cannot be broken down into smaller particles.

The correct order of the alimentary canal , also known as the gastrointestinal (GI) tract : Mouth : Food enters the mouth, where it's chewed and mixed with saliva. Oesophagus : Food passes through the oesophagus , a muscular tube that transports it to the stomach. Stomach : The stomach secretes gastric juices to digest proteins and fats. Small Intestine : Nutrient absorption occurs in the small intestine , where specialized structures like villi and microvilli increase the surface area.

Valency is the combining capacity of an atom to form molecules or compounds. It depends on the number of electrons an atom can lose, gain, or share to complete its outer shell.

The word ‘ Scientia ’ is derived from the Latin word Scientia which means ‘ knowledge ’. Science involves observation, experimentation, and analysis . The scientific method includes Hypothesis → Experiment → Observation → Conclusion .

The Sun is a star. There are lots of stars, but the Sun is the closest one to Earth. It is the center of our solar system. The Sun is a hot ball of glowing gases. The sun is composed of layers made up almost entirely of hydrogen and helium.

Sound waves are mechanical waves that require a medium (air, water, or solid) to travel. They transport energy , not matter. Particles of the medium vibrate around their mean position but do not move along with the wave. Examples : Speaking, music, and alarms transfer energy through sound waves.

Refraction : Bending of light when it passes from one medium to another. A prism bends light at different angles depending on wavelength. This separation of colors is called dispersion , forming a spectrum. Visible spectrum colors : Red, Orange, Yellow, Green, Blue, Indigo, Violet ( ROYGBIV ).

Thermal energy can be transferred through all three methods: Conduction : Direct transfer between particles in physical contact. Convection : Transfer through the movement of fluids. Radiation : Transfer through electromagnetic waves (e.g., light, radio waves).

Tundra is a cold, treeless region found near the Arctic and Antarctic . Soil is often frozen (permafrost) throughout the year. Vegetation includes mosses, lichens, and low shrubs . Animals adapted: polar bears, arctic foxes, reindeer .

A molecule is the smallest particle of a substance that retains its chemical properties. It is made of two or more atoms chemically bonded together. Examples of molecules: H₂O, O₂, CO₂, NH₃, CH₄. Additional information : An atom is the smallest unit of an element. A compound is a substance formed when different elements combine chemically.

Humans have 20 primary teeth (also known as deciduous or baby teeth). 32 permanent teeth (also known as adult teeth).