General Science · Practice test 1

Correct answer: the Moon slides into the line connecting Earth and the Sun

A solar eclipse happens when the Moon lines up directly between Earth and the Sun, casting a shadow that blocks sunlight along a narrow track on Earth. When Earth instead sits in the middle and casts its shadow on the Moon, that is a lunar eclipse.

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Correct answer: rate at which work is done

Power measures how quickly work gets done, work divided by time, so doing the same job faster requires more power even though the total work is unchanged.

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Correct answer: its axis is tilted relative to its orbit

The roughly 23.5 degree tilt means each hemisphere leans toward the Sun for part of the year and away for another part, changing the angle and hours of sunlight. Distance is the popular wrong answer: Earth is actually nearest the Sun during northern winter.

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Correct answer: The cerebellum

The cerebellum sits at the back and below the cerebrum and fine-tunes posture, balance, and smooth movement. The cerebrum handles thought and voluntary action, and the medulla runs automatic functions like breathing.

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Correct answer: along boundaries between tectonic plates

Plates grind past, pull apart from, or dive beneath one another at their edges, and the stress released there is what shakes the ground. Mapping earthquakes traces the plate boundaries almost exactly.

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Correct answer: convection

Convection moves heat through the bulk movement of a heated fluid, such as air or water, as warmer, less dense fluid rises and cooler fluid sinks to take its place.

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Correct answer: 50 mph

Average speed equals total distance divided by total time, so 150 miles divided by 3 hours gives 50 miles per hour.

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Correct answer: distance

A light-year is how far light travels in a year, roughly six trillion miles. The word year in the name makes time the obvious trap.

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Correct answer: ice caps and glaciers

Around two thirds of fresh water is frozen in ice caps and glaciers, with most of the rest underground. The rivers and lakes people actually draw on hold only a small fraction.

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Correct answer: bone

A tendon anchors a muscle to a bone so that when the muscle contracts, it pulls the bone and produces movement. Ligaments, by contrast, connect bone to bone.

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Correct answer: breaking down sugar with oxygen

Respiration breaks glucose down using oxygen, releasing energy the cell can use and giving off carbon dioxide and water as waste, essentially the reverse of photosynthesis.

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Correct answer: Ultraviolet

Ultraviolet radiation sits just beyond violet light, with a shorter wavelength and higher energy than any visible colour. Infrared, microwaves, and radio waves all have longer wavelengths than visible light.

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Correct answer: amplitude

A sound wave's amplitude, how far its particles are displaced, determines how loud it is perceived to be, while frequency instead determines pitch.

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Correct answer: pancreas

The pancreas releases insulin, which lets cells take glucose out of the blood. When that fails, blood sugar rises, which is the basis of diabetes.

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Correct answer: four cells, each with half the chromosome number

Meiosis involves two rounds of division, producing four sex cells that each carry half the parent's chromosome number, ready to combine with another sex cell at fertilization.

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Correct answer: Richter scale

The Richter scale, and modern equivalents like the moment magnitude scale, measure the energy released by an earthquake. The Beaufort scale rates wind and the Mohs scale rates mineral hardness.

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Correct answer: low annual rainfall

A desert is defined by how little precipitation it receives, not by heat or sand. Antarctica qualifies as a desert, and most deserts support specially adapted plants and animals.

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Correct answer: Messenger RNA

DNA stays in the nucleus, so a working copy of the gene is transcribed into messenger RNA, which travels to a ribosome where the protein is assembled.

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Correct answer: the Sun and Moon pull in roughly the same direction

Spring tides occur near the new and full moon, when the Sun and Moon align and their gravitational pulls combine, producing especially high and low tides.

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Correct answer: troposphere

The troposphere is the lowest layer of the atmosphere, extending up several miles, and it holds nearly all of the water vapour and air movement responsible for weather.

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Correct answer: velocity

Velocity is speed with a direction attached, which is why a car going round a bend at a steady speed still has changing velocity. Acceleration is the rate at which velocity changes.

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Correct answer: Kingdom

From broadest to narrowest, the major ranks run kingdom, phylum, class, order, family, genus, and species, so kingdom groups the most organisms and species the fewest.

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Correct answer: Diamond

The Mohs scale runs from talc at 1 to diamond at 10, ranking minerals by which can scratch which. Granite is a rock made of several minerals rather than a mineral itself.

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Correct answer: H2O

Water is two hydrogen atoms bonded to one oxygen atom. The last choice, H2O2, is hydrogen peroxide, a different compound entirely.

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Correct answer: radiometric dating

Radiometric dating measures how much of a radioactive isotope in a sample has decayed into a stable form; because the decay rate is constant, that ratio reveals the sample's age. Carbon-14 dating is one specific version, useful only for material under about 50,000 years old.

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