The independent variable is the seeds.
Build several models of his tree house out of different materials, and see which model holds up best to wind, water, and ice.
Very true.
It harms our atmosphere, thus effecting climate. Which can kill and sometimes nearly cause organisms to go extinct. It corrupts our air, which is very unhealthy, and can cause lung cancer, and harm our breathing patterns. Which can shorten life expectancy.
Stay clean, and I hope this helps! :) <span />
Changes in the amount of sea ice can disrupt normal ocean circulation, thereby leading to changes in global climate. Even a small increase in temperature can lead to greater warming over time, making the polar regions the most sensitive areas to climate change on Earth
