If you have a Raid 0 array & one of the HDDs breaks, you lose all the data on all the disks in that array.

The first R is for Redundant, the whole point is supposed to be about getting data redundancy so that if a HDD breaks you don't loose data.

Raid 1 is mirroring so the same data is on all drives in the array.
If one breaks, you still have the data so its ok but from 2 disks you only get the usable space of 1.

Raid 5 requires 3 drives minimum & has data striped across two a-la raid 0 but uses the 3rd for error checking data.
If one of the raid 5 disks breaks, you can replace it without loss of data.
Raid 5 has usable space of 2 disks from minimum of 3 disks.