All Free Everyday Science MCQs with Answers

741. The difference in the duration of day and night increases as one moves from:_________?

• A. West to East
• B. East and west of the prime meridian
• C. Equator to poles
• D. None of these

Explanation: Day-night inequality increases from the equator toward the poles because Earth's axial tilt produces greater seasonal variation at higher latitudes. At the equator, day and night remain nearly equal throughout the year.

742. Underground water and the water on the earth's surface is called ?

• A. Mezosphere
• B. Ionosphere
• C. Hydrosphere
• D. None of these

Explanation: The hydrosphere includes all of Earth’s water, including oceans, rivers, glaciers, groundwater and water vapour. Mesosphere and ionosphere are layers or regions of the atmosphere, not water reservoirs.

743. Scientific study of the Algae is known as ___________?

• A. Phycology
• B. Pomology
• C. Oneriology
• D. Trichology

Explanation: Phycology, also called algology, is the branch of biology concerned with algae. Pomology studies fruits, while trichology concerns hair.

744. The Scientific Study of Caves are know as _________ ?

• A. Haematology
• B. Speleology
• C. Oology
• D. Oneriology

Explanation: Speleology is the scientific study and exploration of caves, including their geology, biology and formation. Haematology deals with blood, whereas oology concerns eggs.

745. The scientific study of spiders is called __________ ?

• A. Arachnology
• B. Osteology
• C. Pomology
• D. None of these

Explanation: Arachnology studies spiders and other arachnids such as scorpions and ticks. Osteology is the study of bones, so it is unrelated despite the similar scientific suffix.

746. Hen and chicken disorder is associated with__________ ?

• A. Mango
• B. Grapes
• C. Tomato
• D. Guava

Explanation: Hen-and-chicken disorder is a physiological disorder of grapes in which berries develop unevenly, with some remaining small and seedless. It is therefore associated with grape cultivation rather than mango, tomato, or guava.

747. Which of the following is the flightless bird?

• A. Pavo cristatus
• B. kakapo
• C. Passer
• D. None of these

Explanation: The kakapo is a flightless nocturnal parrot native to New Zealand. Pavo cristatus, the peacock, and Passer, the sparrow genus, are flying birds.

748. The principal constituent of the atmosphere of the Earth is?

• A. Oxygen
• B. Carbon
• C. Hydrogen
• D. Nitrogen

Explanation: Nitrogen makes up about 78% of Earth’s atmosphere, making it the principal constituent. Oxygen is second at about 21%, while carbon and hydrogen occur mainly in compounds and trace gases.

749. Which layer of the atmosphere lies close to the earth?

• A. Stratosphere
• B. Mesosphere
• C. Troposphere
• D. Thermosphere

Explanation: The troposphere is the lowest atmospheric layer and lies directly next to Earth's surface. Most clouds, weather and atmospheric water vapour are found in this layer.

750. Identify the blackest fish in the oceans?

• A. Black Seafish
• B. Black Dragon fish
• C. Black Sea Horse
• D. Black Gillfish

Explanation: The black dragonfish is noted for its extremely dark, light-absorbing body, an adaptation that helps it remain concealed in the deep ocean. The other names are not recognised standard examples of the blackest fish.