A P E X
?What is an index fossil?
A. A fossil this is found all over the world
B. A fossil this is from an animal that did not evolve
C. A fossil that is more than 60,000 years old
D. A fossil found in rocks from one time period

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link:

the  different  of  these  two  are  that  they  differently  handle  their  team.

an  expressive  leader  focuses  on  the  task  at  hand  and  make  sures  that  their  goal  is  achieved.  they  accurately  finish  the  task.  an  instrumental  leader  on  the  other  hand  works  on  the  unity  of  the  group,  they  care  more  about  their  employees.  all  the  while  creating  a  good  environment.