Questions

Paging is a memory management technique in which process address space is broken into blocks of the same size called pages.

1) ability to support multiple processors
2) virtual storage
3) source level debugging

TIME is what we can measure in Years, Months, Days, Hours, Minutes and Seconds but we cannot see.

All the above will stay where they are when they goes off. Basically anything that can swithch on or off will come under this.

Longest railway bridge (Lower Zambesi ) is located in Africa

The receptor molecules, which receive signals from outside the cell, passing the signal to the inside.

In order for a nerve cell, or any cell, to perceive its environment, it needs a sensory apparatus. And for an individual cell, most of that sensation is derived at the cell surface. So, it expresses on its cell surface proteins that span across the membrane.

In the outside world, these proteins can act to receive signals, catching molecules on the outside and then as the molecule passes to the inside of the cell, they can send signals like alarm signals that can tell the cell that a particular molecule is outside.

Hence, here B is the receptor cell.