Which stroke of a four-cycle naturally aspirated engine creates manifold vacuum?

The letter "O" as assigned to tool steels designates:

A) Steels that were made from selected ores B) Ostenitic steels C) Over stressed steel D) Oil hardening steels

Pervious concrete is placed over a gravel sub base of ____ inches or more that provides a storage reservoir for rainwater, allowing it to percolate into the ground.

A. 3 B. 6 C. 9 D. 12

A model of a complex electronic system is often simplified and represented as a

A) logic ladder B) block diagram C) flow chart D) timning diagram

If there is a hole in the floor of a structure, the preferred method of protecting workers from falls is to _____

a. cover the opening and label the cover b. place reflective tape around the opening c. post a guard at the opening d. place a warning sign near the opening