Final answer:
The /etc/fstab file is responsible for containing the filesystems that need to be mounted automatically during the Linux boot process.
Step-by-step explanation:
The file that contains the filesystems to be automatically mounted during boot is /etc/fstab. The /etc/fstab file, which stands for filesystem table, is crucial for the Linux operating system. It lists all available disk partitions and their mount points, as well as how these should be initialised and integrated into the larger file system structure. This file is read by various utilities during the startup process to mount necessary filesystems before the system is fully operational. It is important to configure /etc/fstab correctly to ensure a smooth boot process and proper access to necessary filesystems.