=COUNTIF(A2:A5,A2)+COUNTIF(A2:A5,A3) Counts the number of apples (the value in A2), and oranges (the value in A3) in cells A2 through A5. The result is 3. This formula uses COUNTIF twice to specify multiple criteria, one criteria per expression. You could also use the COUNTIFS function.
Punctuated equilibrium. Definition. noun. A theory that describes an evolutionary change happening rapidly and in brief geological events in between the long periods of stasis (or equilibrium). The theory is based on the stasis in fossil records, and when phenotypic evolution occurs, it is localized in rare, rapid events of branching speciation.
D. Overproduction of offspring. Darwin's theory of natural selection states that species tend to overproduce due to limiting resources. This sets up competition or a struggle for existence. Those most fit in that environment are likely to survive, passing those favorable genes on to their offspring. In time, a new species evolves from the accumulation of favorable genes. Punctuated equilibrium is a theory that was formulated after Darwin's theory and it states that species remain relatively stable for long periods of time and then, due to some natural catastrophe, change rapidly in a short period of time.