The question requires selecting two true statements about micro-partitions. Option A is correct because micro-partitions are approximately 16MB in size after compression, as confirmed by multiple community comments and the clarification that uncompressed data is 50-500MB but compressed to around 16MB. Option C is correct because micro-partitions are immutable, meaning once created, they cannot be modified, which aligns with Snowflake's architecture and community consensus. Option B is incorrect because compression is automatic and not dependent on a COMPRESS=TRUE setting; the default behavior compresses data. Option D is incorrect because encryption applies to all editions of Snowflake, not just Enterprise and above, ensuring data security across all tiers.