Answer:
Support
Posture
Protection
Explanation:
Support – the skeleton keeps the body upright and provides a framework for muscle and tissue attachment.
Posture – the skeleton gives the correct shape to our body.
Protection – the bones of the skeleton protect the internal organs and reduce the risk of injury on impact.
I'm not sure, I think it's option A.
Let me know if I'm wrong!
Explanation:
Let f is the frequency of an oscillation and T is the period of the oscillation. There exists an inverse relationship between the frequency and the time period of the oscillation. Mathematically, it is given by :
Also, 
So,
The time taken to complete one oscillation is called the period of the oscillation and the number of oscillation is called the frequency if an oscillation.
Here we deal with a lever law. It states that product of force and distance from a fixed point on a lever is equal on both sides.
F₁*d₁ = F₂*d₂
By analysing this formula we can see that applying small force on a great length equals great force on a small length.
To remove nail we need to apply certain force. If we use F₁ for this required force we can see that on other side we need to apply certain force. If we have greater arm length we need smaller force. In a crowbar arm length along which we apply force is greater than length of our arm. This leads to a conclusion that we need smaller force when using crowbar. Depending on the length of a nail it is possible that we need to apply force that is greater than force required to remove nail.
