1.) D.) High birth rates
As most of the countries in the world, Australia and New Zealand have some issues that make them problems, but the high birth rates is not one of those issues. These two nations do not have high birth rates, in fact they have low birth rates. The governments of these nations try to convince the people to have more children as they are starting to face an aging population which is very damaging for the economy. The younger population though is not that interested in having lot of children, and some don't want to have children at all.
2.) B.)They crowd out native animal territories
The invasive species are species that have been introduced into a new environment, be it naturally or because of the humans. These species more often than not manage to outcrowd the native species territories. This happens because the invasive species are often able to reproduce quicker. They tend to outcompete the native species, and also the native species do not have a defense mechanism against them. This results in explosion of the populations of invasive species, while the native species have significant decrease or go extinct.