Yes. Any iPhone after the iPhone 4S comes with Siri, but you have to choose to enable it when you're setting up the iPhone for the first time. You can always change your mind (and other Siri settings) later, by going to the Settings app.
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yes
yes it has Siri
No. Siri is only Available for the iPhone 4S!
A key difference between an iPhone 5C and an iPhone 5 is the support for more 4G LTE frequency bands by iPhone 5C.
You can not get Siri if you jailbreak a iphone 4. In order to get Siri you have to download the app.
The iPhone 5c is newer. The 5c came out on September 20, 2013 and the 5 came out on September 21, 2012.
The iphone 5c is bigger than the iphone 5.
The IPhone Siri was named after a man's daughter. This man wanted to name it Siri because of his daughter, Siri, and made up a abbreviation for some thing. For real, the IPhone Siri is S.I.R.I.
Both the iPhone 5 and the 5c have 4 inch screens. The frame of the 5c is slightly larger than the the iPhone 5.
No, the iPhone 5s, iPhone 5c and iPhone 5 do not fit into the same cases.
Between iPod Touch 5th generation and iPhone 5c, iPhone 5c is much better.
You will have to download the IOS 8 on the iPhone 5c. This is easy to install.