Why are nonnative species a threat to biodiversity a they often use up resources that other organisms need b they are not able to successfully breed in the wild c they release many pollen in to the environments d they easily contact and spread diseases to other organisms

The correct answer is A

Answer after wwii, communist countries in eastern europe formed the warsaw pack, a military alliance, and comecon, an economic alliance;

Humans have survived and thrived in mexico city by using technology to create greater access to land. when the spanish conquered the aztec capital, tenochtitlan, in the 16th century, they built mexico city by draining the lakes and filling in the lake water to create more arable land for agriculture. this technique of land reclamation has continued to be fundamental to human civilization in mexico city.