1) Explanation

Let's break down the sentence blank by blank, looking for the logical connections.
- Blank (i): "The eminent sociobiologist demonstrated a relationship between social status and (i) $\qquad$ to infectious disease in male macaque monkeys:"
- The core here is a relationship between "social status" and something "to infectious disease." Diseases are something an organism might be vulnerable to or immune from. The nature of the blank should indicate how social status influences the interaction with infectious disease.
- A. susceptibility: The state or fact of being likely or liable to be influenced or harmed by a particular thing. If there's a relationship between social status and susceptibility to disease, it means higher status might lead to lower susceptibility (or vice-versa). This makes perfect sense.
- B. impartiality: Equal treatment of all rivals or disputants; fairness. This refers to fairness and is irrelevant to disease.
- C. dominance: Power and influence over others. While social status relates to dominance, the blank is connected to "infectious disease," not directly to power itself.

So, Blank (i) is A. susceptibility.
- Blank (ii): "he then suggested that wealthy humans are also less prone to (ii) $\qquad$ ."
- This part of the sentence applies the findings from macaque monkeys to humans. If macaque monkeys show a relationship between social status and susceptibility to infectious disease, then the analogous idea for humans would be that wealthy humans (high social status) are less prone to getting sick or disease.
- D. compensation: Something, typically money, awarded to someone in recognition of loss, suffering, or injury. This is irrelevant to being prone to something.
- E. sickness: The state of being ill; a particular illness or disease. This is a direct and logical parallel to "infectious disease" from the first part of the sentence. If they're less prone to something, it's less prone to becoming ill or contracting a disease.
- F. mobility: The ability to move or be moved freely and easily. This is irrelevant.

So, Blank (ii) is E. sickness.
Putting It Together:
"The eminent sociobiologist demonstrated a relationship between social status and susceptibility to infectious disease in male macaque monkeys: he then suggested that wealthy humans are also less prone to sickness."

This creates a coherent and logical argument: the study found a link between social standing and vulnerability to disease in monkeys, and this finding was then extrapolated to suggest a similar pattern regarding wealth and illness in humans.