The echo sounder is an instrument that measures depth based on the principle of echo-wave reflections transmitted through a wave generatpr in which the wave-time return is being noted. The two pieces of information needed to determine ocean depth are: velocity of the wave and the return time of the wave.
Answer:
objects observed in extra-galactic space (deep space) are shifting away or receding away from earth
It seems that you have missed the necessary options for us to answer this question so I had to look for it. Anyway, here is the answer. Varicose veins seen in the superficial veins of the legs are unsightly and often treated by surgically removing them. however, even without these veins being present, the return of all blood toward the heart from the legs is not diminished primarily because <span>blood can still return via the deep veins. Hope this helps.</span>
Because the species of finches on the Galápagos island have various appearances but still mate with other finches and produce fertile offspring making it is difficult for scientists to distinguish between two groups of individuals as separate species.
<h3>What is the island of Galápagos?</h3>
The Pacific Ocean island of Galápagos is located to the west of Ecuador. It is a volcanic island known for its diverse and endemic types of living things.
<h3>Why is it difficult to find new species in Finches?</h3>
Charles Darwin spent several years studying the many species of finches on the Galápagos island. He saw a great deal of variation in these finches, which supports the hypothesis of natural selection.
However. it is challenging for scientists to discern between two separate species because the species of finches on the Galápagos island have a variety of features that are different but still mate with other finches and produce fertile offspring.
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