A. Earth's magnetic field reverses over time; the changes show that seafloor spreading has taken place over time.
Explanation:
The pattern of the magnetic minerals in seafloor ridges are aligned in a repeating pattern because the earth's magnetic field reverses overtime.
This provides evidence because the changes shows that the sea floor spreading has taken place over time.
- The concept of sea floor spreading was first suggested by Harry Hess in the early 1960's.
- Using sophisticated tools, he was able to discover stripe patterns of magnetic minerals in rocks.
- The earth can be likened to a giant bar magnet
- The geomagnetic field originates from the core where the movement of molten metals induces magnetism.
- In a fresh cooling magma, the metallic minerals are able to align their domains with the prevailing magnetic field.
- At some point the magnetic field is normal with a very strong intensity. At other times the intensity is low and it reverses.
- The minerals keeps track of the changes.
- This leads to striped pattern that has been used to suggest sea floor spreading.
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Answer:
Option 3, Chromatids remain attached to one another until anaphase
Explanation:
Centromere lies at the center, end or other points of the chromosome and joins the two sister chromatids. During cell division, the spindle fibers attaches at the centromere and detaches the chromosomes during the anaphase of the cell division to ensure that each daughter cell gets equal number of chromosomes at the end of mitosis. Centromere plays an essential role in the separation of chromosomes.
Hence, option 3 is correct
Answer:
a To provide cows and other live stock with vaccines so diseased do not spread among farmers and cattle herders.
Explanation:
because that one makes the most sense and it is true