Why were diseases like measles and influenza so catastrophic for Native American populations?

Their traditional medicine was ineffective against all foreign germs.

The diseases were deliberately spread as a primary tool of conquest from the start.

They had no prior exposure and therefore lacked any built-up immunity.

The climate of the Americas caused the European germs to become more deadly.

The text implies that the initial spread of diseases by Europeans was primarily...

a result of trading infected goods.

resistance to disease acquired through generations of exposure.

advanced medical knowledge and access to effective cures.

ability to quarantine sick individuals from the healthy.

cultural practices that promoted superior hygiene and sanitation.

The introduction of European livestock that overgrazed the land.

The spread of Old World diseases to which they had no natural immunity.

The establishment of new trade routes that disrupted local economies.

The forced labor systems implemented by European colonists.