Answer:
directional selection
Explanation:
direction is where all organisms evolve to one area
B) damming rivers and lakes
Trilobites are found worldwide and evolved rapidly, making them easily distinguishable from trilobites of other time periods
Errors that may happen in the execution of a factual examination outline. Kinds of trial error incorporate human error or missteps in information section; methodical error, or oversights in the outline of the investigation itself; or irregular mistake, caused by natural conditions or other capricious variables.
In meiosis , the no of chromosomes in the daughter cells reduces into half no of that in the initial cell :18