Answer:
B. So you can always see the entire object at the higher magnification
Explanation:
A microscope is used to view objects smaller than the naked or unaided eyes can see. The objective lens, in conjunction with the occular or eye lens, is used to achieve this purpose. The objective lens are of different magnifications as follows: 10X, 40X, 100X etc.
However, as the magnification increases i.e. higher objective, the object in the field of view becomes smaller and less focused. Hence, the object in the field of view must first be centered at a lower magnification/objective lens before changing to a higher one in order for the entire object to be seen at a higher magnification.
secondary succesion takes place
Answer: D. A river separates members of a squirrel population that used to occupy the same geographical area.
Explanation:
Allopathic Speciation occurs when a geographic barrier (river, mountain, or canyon) separates members of a population
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Answer:
James Watson and Francis Crick solved the structure of DNA. Rosalind Franklin and Maurice Wilkins, also contributed to this discovery.
Explanation:
Because of the soil the rocks are in. If They stayed in that soil for a while which affected the compounds, shifting the mineral composition.
