There was no need to. They must have been able to survive just fine without the use of other cells
Answer:
0.08735 kgm²
Explanation:
m = Mass of lower leg = 5 kg
L = Length of leg = 18 cm
g = Acceleration due to gravity = 9.81 m/s²
f = Frequency = 1.6 Hz
I = Moment of inertia
Time period is given by

Also

So,

The moment of inertia of the lower leg is 0.08735 kgm²
Here, you need to use your "Protractor" as it is given in the question, but we can calculate the value with the help of our mathematical calculation too:
[ Protractor can be use only in real life, not here ]
Draw an imaginary line from initial position to final position.
Now, In that triangle, tan x = P/B
tan x = 1.4 / 2
tan x = 0.70
x = tan⁻¹ (0.70)
x = 35 [ tan 35 = 0.70 ]
In short, Your Answer would be 35 degrees
Hope this helps!