Imagine you are studying leaf size in a large population of plants over several years. In one year of your study there is a below-average amount of rainfall, and the following year the average leaf size in the population is smaller than before. However, the amount of variation in leaf size is the same and the population size doesn't change. Other scientists have done experiments showing that small leaves are better adapted to dry conditions than large leaves. What has most likely occurred?

vote read

explanation:

plate tectonics and volcanic euptions

over time, plate tectonic processes cause continents to move to different positions on the globe.

for example, britain was near to the equator 300 million years ago, and therefore was hotter than it is today. for further details look at our climate through time poster or online map.

the movement of the plates also causes volcanoes and mountains to form and these too can contribute to a change in climate.

mountain ranges formed by plate tectonics. large mountain chains can influence the circulation of air around the globe, and consequently influence the climate.   warm air might be deflected somewhere cooler by the mountains.

i am going to guess that it is co2.