All Free Everyday Science MCQs with Answers

721. _______________ causes biomagnification problem in the Ecosystem.

• A. Lead
• B. Mercury
• C. Chromium
• D. Copper

Explanation: Mercury accumulates in organisms and becomes increasingly concentrated at successive levels of a food chain, especially in fish-eating animals. This increase in concentration is called biomagnification.

722. The process in which seed grows in to a new plant is called ______?

• A. Fertilization
• B. Germination
• C. Vernalization
• D. None of these

Explanation: Germination begins when a seed absorbs water and resumes growth, producing a root and shoot that develop into a new plant. Fertilization forms the seed, whereas vernalization is cold treatment that promotes flowering.

723. Which of the following are Biodegradable ___________?

• A. Cans
• B. Dead Plants
• C. Glass
• D. None of these

Explanation: Dead plants are biodegradable because microorganisms can break their organic matter into simpler substances. Cans and glass generally persist much longer and are non-biodegradable in ordinary conditions.

724. Which of the following are non-biodegradable materials ______?

• A. Dead Animals
• B. Plastics
• C. Bread
• D. None of these

Explanation: Plastic is non-biodegradable because most microorganisms cannot naturally decompose its long polymer chains. Dead animals and bread are organic materials that decompose relatively readily.

725. The main cause of air pollution is __________?

• A. Burning Of Fuels
• B. Forests
• C. Fertilizers
• D. None of these

Explanation: Burning fuels releases smoke, carbon monoxide, nitrogen oxides, sulphur compounds and particulate matter into the air. Forests generally remove carbon dioxide, while fertilizers mainly cause soil and water pollution, although they can also contribute to air pollution.

726. Electrostatic precipitator is used to control?

• A. Air pollution
• B. Water pollution
• C. Solid waste
• D. Noise pollution

Explanation: An electrostatic precipitator removes dust and fine particulate matter from industrial exhaust by electrically charging particles and collecting them on oppositely charged plates. It therefore controls air pollution rather than water, solid-waste or noise pollution.

727. The atmospheric air is held to the Earth by?

• A. gravity
• B. winds
• C. clouds
• D. rotation of the Earth

Explanation: Earth’s gravity attracts the gases in the atmosphere and keeps them from escaping into space. Winds only move air within the atmosphere; they do not hold it to Earth.

728. Pluviometer measures ___________?

• A. Wind
• B. Strength of Plywood
• C. Rainfall
• D. None of these

Explanation: A pluviometer, also called a rain gauge, collects and measures the amount of rainfall over a period. It does not measure wind speed or strength of materials.

729. Heat transfer horizontally within the atmosphere is called?

• A. Conduction
• B. Convection
• C. Absorption
• D. Advection

Explanation: Advection is the horizontal movement of heat or another atmospheric property by moving air. Convection mainly describes vertical transfer caused by rising warm air and sinking cool air.

730. Which one of the following wavelengths of light is most effective in photosynthesis?

• A. Blue
• B. Green
• C. Orange
• D. Yellow

Explanation: Chlorophyll absorbs blue and red light most efficiently for photosynthesis, while green light is largely reflected. Among the listed choices, blue is therefore the best answer.