Questions

Personal flotation devices (PFDs), have life span upto it is damaged. Hence, When it has a torn strap you should discard a PFD.

Rust forms when oxygen reacts with chemicals in rocks, and that is often the case with many other elements in general. Like a copper nail being exposed to the air will rust.

Galton's whistle is also called as Dogs whistle or silent whistle, is a type of whistle that emits sound in the ultrasonic range, which people cannot hear but some other animals can, including dogs and domestic cats, and is used in their training.

Kernel follows Round Robin scheme choosing a swap device among the multiple swap devices in Unix System V.

Pericles