Birds have great vision and can see throughout night and day
A) Crossing over is the mechanism of genetic variation that results from the exchange of gene segments between non-sister chomatids.
Answer: [D]: "oceans" .
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Note: Among the answer choices given—{aquifers, glaciers, lakes, oceans}—oceans are the saltiest (VERY salty—requiring "desalination" in order to obtain potable water.
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An organ is a group of tissues working together to perform specific functions. An example of an organ is the heart.
Answer:
Los cromosomas se forman cuando la cromatina se condensa durante la división celular, sólo en este proceso son visibles. Este proceso es muy importante, ya que esta condensación o sobre enrollamiento, hace que se economice espacio, si esto no sucediera, la cromatina excedería el espacio nuclear disponible.