I installed Ubuntu along side Win10. I was informed that there should be a grub menu that lets me choose which OS i want to load. But now it straight up loads Ubuntu. I provided an attachment of my partition. Sda1 and sda2 are my Win10 partitions. The whole of sda4 is Ubuntu. Is there something wrong here? Was the MBR overwritten by Ubuntu?

GParted.jpg
The BIOS boot option is as below. There is an entry for Ubuntu but no Windows. Is this normal?
BIOS.jpg

Thanks in advance.