The time between contact with a disease organism and the appearance of the first symptoms is called the _________________ period

On the basis of strength to unit weight, wood has a tensile strength compared to:

A) masonry. B) concrete. C) precast concrete. D) steel.

Which of the following can be used as a contrast medium during a radiological procedure?

A) Carbon dioxide B) Iodine C) Air D) All of the above