<h3>Answers:
</h3><h2>38. (B) Wavelength
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In physics, the wavelength is the spatial phase of a periodic wave—the length over which the wave's shape repeats. It is thus the inverse of the spatial frequency. Wavelength is normally defined by considering the distance between consecutive corresponding points of the very phase, such as crests, troughs, or zero crossings and is a characteristic of both travelling waves and standing waves, as well as other spatial wave patterns
<h2>39. FALSE
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Doppler echocardiography is a method that uses Doppler ultrasonography to study the heart. An echocardiogram uses high-frequency sound waves to generate an image of the heart while the use of Doppler technology allows determination of the speed and control of blood flow by utilizing the Doppler effect.
<h2>40. (B) Alfred Wegener
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In 1912 Alfred Wegener (1880-1930) marked the same thing and suggested that the continents were once concentrated into a single protocontinent which he called Pangaea (meaning "all lands"), and over time they have sailed apart into their current distribution.
<h2>41. FALSE
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It covers the upper mantle and both the continental and oceanic crust. The mantle’s convective motions break the lithosphere into plates and move them about the surface of the planet. These plates may run away from, move by, or oppose with each other. This method forms ocean basins, shifts continents, and pushes up mountains.
<h2>42. FALSE
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The Earth is split up into an inner core which is often made of iron and then there's an outer silicate part, most of which is described the mantle, and then the crust is the surface that sits on top. Now, the mantle is absolutely solid, but because the Earth is so hot inside, what that solid mantle does is convect.
<h2>43. TRUE</h2>
Mountain composition relates to the geological processes that underlie the formation of mountains. These methods are connected with large-scale movements of the Earth's crust (tectonic plates). Folding, faulting, volcanic activity, igneous intrusion and metamorphism can all be elements of the organic process of mountain building. The formation of mountains is not significantly related to the geological structures found on it.
<h2>44. (B) Conduction</h2>
The variation of energy, such as heat or an electric charge, through a substance. In heat conduction, energy is given from molecule to molecule by direct contact; the molecules themselves do not significantly change position, but simply vibrate more or less quickly against each other.
<h2>45. (C) Convection</h2>
When a liquid, such as air or a liquid, is heated and then moves away from the source, it provides the thermal energy along. This kind of heat transfer is called convection. The fluid above a hot surface increases, becomes less dense, and rises.
