Disk Partitions

My dell Inspiron 15z 5523 is too much slow and active time in task manager is at 100% all the time. Now i Formatted the laptop. Now i See these partitions, number of recovery partitions and a EFI Sysytem Partitions.

1. Do I really need to keep this drive or can I delete it. Could anyone tell me what is the pros and cons of removing it

2.What is EFI System Partitions?

3. As you can see there are two disks. and Disk 0 is SSD(30GB) as it showing in task manager performance tab. Is this laptop comes with SSD because i didn't added any extra disk.

4.If recovery drives are not able to delete then is it possible to merge all recovery partitions to one.