1.when air is cold, it has less ______.

Question

2.the expansion joints _______ when it is cold outside.
3.the expansion joints ______ when it is hot outside.
4.what might happen to a road without expansion joints?

The _____ is a blank need answer please and 4 need it to be short please. and thankyou for your help.

Answer 1

1. less density?
2. shrink
3. expand
4. the road will crack

i think.