Answer:
b. Friction decreased when he went from pavement to ice and then increased two more times.
Explanation:
Frictional force depends on the normal force of the surface and a friction coefficient.
Since we're talking about the same car, the value of 
will remain constant whereas μ will represent the change in the frictional coefficient of the surface. Now we consider the different surfaces, cars will slide in an icy road which means that the frictional coefficient is smaller than the pavement.
After Joshua returns to the pavement road, the resulting frictional force increases and will do so one more time when he reaches the gravel road. Gravel roads have greater frictional coefficients than pavement roads which means the frictional force will increase a second time.
It protects the electrical appliance and the person from electrical shocks/faults.
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Eight electrons surrounding each non-hydrogen atom is the optimal electronic arrangement for covalent molecules because it is needed to achieve an octet structure and is necessary to fill both the s and p subshells of electrons.
<h3>What is Covalent bonding?</h3>
This is the type of bonding which involves the sharing of electrons between atoms of an element.
This is done to achieve an octet configuration thereby making them stable and less reactive thereby making it the most appropriate choice.
Read more about Covalent bonding here brainly.com/question/3447218
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