Answer:
the amount of alcohol in the blood
The correct option is B. separated by the mediastinum :)
D. Reaction time
Objects falling are moving quickly, and being able to react immediately is the most useful skill in this situation. Being agile or having good balance isn't helpful if the object has reached the ground before you moved.
A repetitive motion is done over and over. Example: many workers in factories or on assembly lines have repetitive jobs - they do they same thing over and over.
