I can give you one:
One of the theories (in which i mostly believe in) is the one when every period of time, the climate changes. Now, we are in the warmth period, but after this period, there will be a cooler climate, and keeps repeating every while (think about the ice age)
Answer:
Explanation: The United States of America and Canada have one of the worlds oldest environmental partnerships. The various ways they're partnering to better the environment include:
1. The U.S. - Canada Air Quality Agreement.
This Agreement was signed in 1991 with the aim of working towards the reduction of air emissions which cause cause acid rain. The Agreement was later expanded in the year 2000 with the goal of reducing transboundary smog emissions under the Ozone Annex.
2. The Great Lakes Water Quality Agreement.
This Agreement was initially signed in 1972, and amended in 2012. The goal of the Agreement is to provide a mechanism that involves the effort and cooperation of both countries, that will be geared toward the protection of the Great Lakes Basin ecosystem.
<span>The precambrian period was a time period that happened billions of years ago. Actually, 4.6 billion years, to be exact. The Earth started to form during this period. Layers of rock, elements of the land and waters, and many other things were developed during this time. The atmosphere had a mind of its own, per se, during this time period. It went through many different changes. The atmosphere went from being extremely cold and galactic to warming and having volcanoes, which allowed for an expansion of life forms.</span>
Two ecozones would be different it they had two different climates
