Answer:
all the details are in the attached picture, the answers are marked with colour.
We can find the volume of a small
pebble with the help of measuring cylinder by using the water displacement
method. <span>The </span>water displacement method<span> <span>is the
process of measuring the volume of an irregularly shaped object by immersing it
in water. </span></span>I am
hoping that this answer has satisfied your query and it will be able to help
you in your endeavor, and if you would like, feel free to ask another question.
Answer:

Explanation:
Given that,
Radius of a spherical shell, r = 0.7 m
Torque acting on the shell, 
Angular acceleration of the shell, 
We need to find the rotational inertia of the shell about the axis of rotation. The relation between the torque and the angular acceleration is given by :

I is the rotational inertia of the shell

So, the rotational inertia of the shell is
.
The first one is C. Hope this helps!! If you need anymore help just message me and I will try to get back to you quickly and help in any way i can!