Ais the figurative place where a person locates the source of responsibility in his or her life.
a. metabolic syndrome
b. cardio decline
c. rheumatic disease
d. insulin resistance

Metabolic Syndrome is and incurable but treatable cluster of disease that cause an increase in the chance of heart attacks and heart problems.

Rheumatic disease or rheumatic disorder is an umbrella term for conditions causing chronic, often intermittent pain affecting the joints and/or connective tissue. The study of, and therapeutic interventions in, such disorders is called rheumatology

Insulin Resistance is a resistance to the hormone insulin, resulting in increasing blood sugar.

Cardio Decline is when a person starts to break down and gain more weight, causing them to lose strength. It has to do with the age of the person.

What I could see is using Cardio Decline to fill in the blank as a figure of speech, a metaphor per say. The answer is B. When they start to realize their inevitable life with their Cardio Declining, it could help them see what responsibilities they have to full fill.

Your answer is  d.)relationship between pressure and air volume and led to the understanding of how respiration works