Which two statements are true about the logical storage structure of an Oracle database?

Extents are not guaranteed to be physically contiguous on disk; with features such as Oracle ASM striping or certain OS file systems, the blocks that make up an extent may reside at non-contiguous physical locations.

An extent is allocated exclusively to a single segment and cannot span multiple segments; each segment manages its own collection of extents independently.

An Oracle data block can span multiple OS blocks when DB_BLOCK_SIZE exceeds the OS block size - for example, an 8KB Oracle block on a file system with 4KB OS blocks occupies two OS blocks.

Oracle supports nonstandard block sizes at the tablespace level using the BLOCKSIZE clause; individual tablespaces can use block sizes (2K, 4K, 8K, 16K, 32K) that differ from the instance default set by DB_BLOCK_SIZE, enabling storage and performance tuning flexibility.

The Oracle data block is the finest granularity at which the database engine reads from and writes to data files; all I/O operations on data files are performed in whole data block units, making it the fundamental I/O unit.