All Free Everyday Science MCQs with Answers

851. Barnacles growing on the back of whale is an example for ________________?

• A. mutualism
• B. parasitism
• C. amensalism
• D. commensalism

Explanation: Barnacles gain transport and access to food while the whale is generally neither helped nor harmed, making this commensalism. Mutualism would benefit both organisms, whereas parasitism harms the host.

852. Fine organic or inorganic particles suspended in air is called _______________?

• A. particulate pollutant
• B. gaseous pollutant
• C. aerosol
• D. none of these

Explanation: An aerosol is a suspension of fine solid particles or liquid droplets in a gas such as air. Particulate pollutant describes harmful particles specifically, while aerosol is the broader physical term used here.

853. Fog that most often forms as warm rain falls into a cold layer of surface air is called ______________?

• A. Radiation fog
• B. Evaporation (mixing) fog
• C. Advection fog
• D. Upslope fog

Explanation: Warm raindrops evaporate as they fall into colder surface air, adding moisture that may reach saturation and form evaporation or mixing fog. Radiation fog forms mainly when the ground cools by night-time radiation.

854. When oil and gas resources are burnt they kill many forests and lakes by ________________ ?

• A. deforestation
• B. water pollution
• C. acid rain
• D. forest fire

Explanation: Burning fossil fuels releases sulfur dioxide and nitrogen oxides, which react in the atmosphere to form acids. Their deposition damages forests and acidifies lakes, producing acid rain.

855. The pyramid of energy in any ecosystem is _________?

• A. Always upright
• B. May be upright or invented
• C. Always inverted
• D. Always Circle

Explanation: An energy pyramid is always upright because energy is lost as heat at each trophic transfer, leaving progressively less energy for higher consumers. Unlike some pyramids of numbers or biomass, it cannot be inverted.

856. In middle latitudes, which cloud will have the lowest base ________________________ ?

• A. Cirrostratus
• B. Stratocumulus
• C. Altocumulus
• D. Cirrus

Explanation: Stratocumulus is a low-level cloud, so its base is lower than those of middle-level altocumulus and high-level cirrus or cirrostratus. The cloud name and altitude category provide the useful clue.

857. The blueness of the sky is mainly due to _____________?

• A. The scattering of sunlight by air molecules
• B. The presence of water vapor
• C. Absorption of blue light by the air
• D. Emission of blue light by the atmosphere

Explanation: Air molecules scatter short-wavelength blue light more strongly than longer-wavelength red light, so scattered blue light reaches the observer from all directions. Water vapour is not the main cause of the sky's blue colour.

858. The atmosphere near the earth's surface is "heated from below." Which of the following does not significantly contribute to this heating _____________________?

• A. Conduction of heat upward from a hot surface
• B. Convection from a hot surface
• C. Absorption of infrared energy that has been radiated from the surface
• D. Heat energy from the earth's interior

Explanation: The surface warms the lower atmosphere through conduction, convection and absorption of outgoing infrared radiation. Heat from Earth's interior is negligible compared with solar energy at the surface.

859. The gradual physiological adjustment to slowly changing new environmental conditions is known as _____________________?

• A. Selection
• B. Introduction
• C. Acclimatization
• D. Quarantine

Explanation: Acclimatization is the gradual physiological adjustment of an individual to a changed environment, such as reduced oxygen at high altitude. Selection changes populations across generations, not an individual's adjustment.

860. Salinization is ___________?

• A. Accumulation of salts in water
• B. Accumulation of salts in soil
• C. Accumulation of salts in body
• D. Accumulation of salts in animals

Explanation: Salinization is the build-up of soluble salts in soil, often caused by irrigation and evaporation in dry regions. Excess soil salt makes it difficult for plants to absorb water.