What's the correct answer to this question?

In 1980, alfa romeo introduced the first system to smooth a rough idle caused by ignition and camshaft timing changes.

Question 11 of 13 (1 point) jump to question: a stairway, ladder, or ramp must be present in excavations in which of the following situations? a. all trenches must have access/egress b. the trench is more than 15 feet wide but only 1 ½ feet deep c. the trench is more than 4 feet deep and the devices must be within 25 feet of all workers

The solid that is formed and usually sinks to the bottom of a solution is the