Help Some Quick Questions . . .

[PKW57]

A few quick questions that I hope will only require quick answers:

I have 3 location services. I understand the difference between Network Location and GPS, and that Google Location Services is GPS that 'spys' on me to a certain extent with my permission.

1. Which one uses the least power?
2. How can I tell which native apps need which locations service?

What's the best free anti virus/malware program? Norton's $30 price tag is ridiculous.

Thanks in advance . . . .