Question

European rabbits were introduced to Australia in 1859. The rabbits reproduced rapidly in their new environment, displaced other animals and overgrazed vegetation. In an attempt to reduce the rabbit population, a deadly virus was introduced in 1951. When the virus was first introduced, the rabbits died in large numbers, but the death rate decreased over time.

Answer 1

Natural selection favored rabbits that were resistant to the virus.

Step-by-step explanation:

Answer 2

The dead rates decreased over time because the rabbit's system developed resistance to the virus over time.

Step-by-step explanation:

As time goes by, the rabbits give birth to more resistant young ones.

This is due to mutation in the line of antiviral resistance.

The resistance strengthens over time making the virus effect to the rabbits weak.

This type of resistance can be avoided through introducing a different kind of virus after a while.