What we think we know

I have this habit of watching at least 2-4 videos of TED talks. For those who haven't heard of it, it's a website which gathers videos from intellectual conferences where they spread ideas (mostly people who are really into a specific sphere). I wanted to ask your opinion on this video about knowledge. If you decide to watch the video, please try to answer his raised questions first:
1. A little seed weighs next to nothing but a tree weighs a lot. Where does all the stuff come from?
2. Can you light a little torch-bulb with a battery, a bulb and one piece of wire?
3. Why is it hotter in summer than winter?
4. What is the shape of the planets orbits in the solar system?
If anyone answers I will post the video to the speaker with answers. By the way, don't worry if you don't answer these questions, some MIT graduates couldn't do it
1. A little seed weighs next to nothing but a tree weighs a lot. Where does all the stuff come from?
2. Can you light a little torch-bulb with a battery, a bulb and one piece of wire?
3. Why is it hotter in summer than winter?
4. What is the shape of the planets orbits in the solar system?
If anyone answers I will post the video to the speaker with answers. By the way, don't worry if you don't answer these questions, some MIT graduates couldn't do it
