So some rocks are radioactive because they have radioisotopes in their nuclei. Also they may have radon gas trapped in their crystals if they are igneous rock. They could also be radioactive due to the fact that the atom of the rock is unstable.
Connecting USB Devices Manually. Choose VM > Removable Devices to connect specific USB devices to your virtual machine. You can connect up to two USB devices at a time. If the physical USB devices are connected to the host computer through a hub, the virtual machine sees only the USB devices, not the hub.
You can configure the virtual DVD or CD drive as either IDE or SCSI, no matter what kind of physical drive you connect it to. In other words, if your host computer has an IDE CD drive, you can set up the virtual machine's drive as either SCSI or IDE and connect it to the host's drive.