Answer:
The outside of a neuron has more sodium ions while at resting state. When a electrical signal is going to pass through, the sodium channels open up first and the positive sodium ions rush inward making the inner side more positive. This is called action potential.
There is layer of fatty substances called as Myelin Sheath over the course of axons. It helps the electrical signal to be transmitted with a fast pace and efficiently over the course.
Here it is given that initial speed of the package will be same as speed of the helicopter

displacement of the package as it is dropped on ground

acceleration is due to gravity

now by kinematics



by solving above equation we have

so it will take 5.2 s to reach the ground
Answer:
Atoms found in nature are either stable or unstable. ... An atom is unstable (radioactive) if these forces are unbalanced; if the nucleus has an excess of internal energy. Instability of an atom's nucleus may result from an excess of either neutrons or protons
It's number three on your worksheet. ;)