Most preinstalled apps can't be uninstalled, but you might be able to Disable them by going to Settings>Apps, tapping Menu>Show System, selecting the app, and seeing if there's a Disable button. This prevents the app from being opened into RAM, and also prevents it from being updated in the Play Store.
Most of Googles apps can be removed/uninstalled like any other app but some of them cannot because they are considered essential to the Android experience.