Good Riddles

Question: I grow from trees and your home,
once I am grown I fall to my doom.

What am I?

Question: What can float but can't sink.

Question: What can you smell but not see. And can be deadly, too.

Question: A horse travels a certain distance each day. Strangely enough, two of its legs travel 30 miles each day and the other two legs travel nearly 31 miles. How is this situation possible?

Question: A man leaves his house in the morning and kisses his wife. On his way home from work he sees that somebody has hit a power line. He immediately knows his wife has died.

How did he know this?