Answer:
The answer is "The threat to internal validity is mortality".
Step-by-step explanation:
It signifies that while in terms of your study, persons were "morning." It usually signifies when people leave the studies. There will be only likely if indeed the experiment lasts a long period that it'll be a substantial danger to validity and reliability because the chance for drops increases. Eight content validity risks are history, maturity, instrument, test, choice, average regress, human engagement, and mortality.
The side of the square is 4 cm since 4x4= 16
The answer is 168 seconds.