Question about bonds

Kids' accounts are cash and some PTRAX (Pimco). I don't pay much attention to bonds, but they asked me if they should continue to hold. They also asked if there was an alternative to cash/bonds, and I said no, not in here. What's the deal?

http://finance.yahoo...X,VFIIX,DPO&d=s
http://finance.yahoo...=...;f=2009&g=v

http://finance.yahoo...s=P...o&c=^GSPC