An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force. This is referred to as interia . If an unbalanced force such as another vehilce hits another, than a persons air bag will then be active . Because when a car is in motion at a constant speed, that’s what will happen when an unbalanced force acts apon it .
Answer: Option (c) is the correct answer.
Explanation:
A chemical reaction is defined as the reaction where a chemical bond will break in order to form a new bond due to the formation of a new substance.
For example, 
Here, NaCl is the new substance that is formed. A chemical reaction will always bring change in chemical composition of a substance.
The production of hydrogen gas from water, the tarnishing of a copper penny, charging a cellular phone and burning a plastic water bottle are all chemical reactions.
Whereas a reaction where no change in chemical composition of a substance takes place is known as a physical reaction.
For example, chopping a log into sawdust will change the shape but it will not bring any change in chemical composition of the substance.
Thus, we can conclude that in the following list, only chopping a log into sawdust is not an example of a chemical reaction.
The 2 trends that are commonly seen in modern concentration
chart , first it is increasing. Since the star of industrial revolution the
amount of co2 increases with time. The second trend is that the temperature
also increases because it is a green house gas which causes the global warming.