Biology

Milo Francis

5 December, 16:09

26

Between 1347 and 1350, the bubonic plague killed nearly half of Europeans. Scientists have discovered that about 10% of the modern descendants of those who survived the plague have a resistance to infection by the Human Immunodeficiency Virus (HIV).

Which hypothesis bestexplains this occurrence?

A. The individuals who survived were not exposed to the plague which enabled their descendants to be resistant to HIV.

B. The individuals who survived the plague passed on genes to their modern descendants which allowed them to be resistant to HIV.

C. The bodies of individuals with a resistance to HIV contain small numbers of the bacteria linked to the plague which enabled them to be resistant to HIV.

D. Individuals who survived the plague have stronger immune systems, and as a result, their descendants have immune systems strong enough to be resistant to HIV.