Which of the following has only one solution

How do i start to solve? would appreciate a walk-thru! a bird sitting 16ft above the ground in an apple tree dislodges an apple. after how many seconds does the apple land on the ground? (assuming that no branches will interfere with it's fall)

Pepe and leo deposits money into their savings account at the end of the month the table shows the account balances. if there pattern of savings continue and neither earns interest nor withdraw any of the money , how will the balance compare after a very long time ?

Type the correct answer in each box, round your answers to the nearest integer 20 25 30 in the figure, the perimeter of hexagon abcdef is approximately w units, and its area is square units