This is clearly indicated on the PRISM Wikipedia page that was linked above.
> PRISM is a code name for a program under which the United States National Security Agency (NSA) collects internet communications from various U.S. internet companies.[1][2][3] The program is also known by the SIGAD US-984XN.[4][5] PRISM collects stored internet communications based on demands made to internet companies such as Google LLC under Section 702 of the FISA Amendments Act of 2008 to turn over any data that match court-approved search terms.
As I've said, that's a detail and splitting hairs. If a sentence has multiple interpretations and one of them is true, but you phrase it in a way that most people interpret the sentence in the wrong way, you are intentionally deceiving people. They should have said "we have never heard the name PRISM" or something like this.
No, that's a separate thing. They do both. See the "you should use both" slide.
https://github.com/iamcryptoki/snowden-archive/blob/master/d...
As to the apple claims that they didn't participate in PRISM, I think they were just lying. Clapper lied to congress as well, so this isn't unheard of. They would likely have breached their government contract by telling the truth. That being said, them having never heard about the program name might be true because it might not have been known to them under that name, but that's just a detail.