The reason why plants go limp when they don't have water for a while A. There is no actual physical change when plants don't have water.
B. Cells sink in because the salt becomes too concentrated and it draws in the cell walls.
C. The cells sink in a little because the central vacuole has very little water in it and becomes concave.
D. None of these were the correct explanation.

are there answer choices to this question? this seems like a question where you have options to choose from.

explanation:

as the height from which the ruler was dropped increased, the speed of the ruler at ryan's hand increased.

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s

snell's law

refractve index = sin incidence / sin refraction