Which is the best definition of a risk factor

A risk factor is any attribute a characteristic or exposure of an individual that increases the chance of developing a disease or injury

A risk factor is any attribute, characteristic or exposure of an individual that increases the likelihood of developing a disease or injury. Some examples of the more important risk factors are underweight, unsafe sex, high blood pressure, tobacco and alcohol consumption, and unsafe water, sanitation and hygiene.

Sodium is the answer

Ican only answer your first question, a machine is like a human body because it's a little similar. they both almost work like the same.